Tunneling protocol vulnerabilities

In ssh in OpenSSH before 10.6, a $ or \ character can occur in a command-line username, leading to injection.

In sshd in OpenSSH before 10.6, the value "none" for a configuration option is sometimes interpreted as a filename but was intended to mean that a feature is disabled.

In sshd in OpenSSH before 10.6, the restrict keyword (in authorized_keys) was supposed to be applicable to tunnel forwarding but was not, a different vulnerability than CVE-2026-73283.

In sshd and ssh in OpenSSH before 10.6, there is no check for whether the maximum packet length is exceeded during decompression of highly compressed data.

In ssh-keygen in OpenSSH before 10.6, certificates could have incorrect expiration times because of Daylight Saving mishandling. There can be a slightly more severe effect on users in certain Antarctic locations.

In sshd and ssh in OpenSSH before 10.6, an LZ77 dictionary coder can be used even though this is contraindicated by the arXiv 2609.07709 "Crossing the Streams" findings.

In sshd in OpenSSH before 10.6, GSSAPIAuthentication authentication state can incorrectly be persisted across authentication attempts.

In sshd in OpenSSH before 10.6, credentials can incorrectly persist after failure of a GSSAPIAuthentication authentication attempt.

In sftp in OpenSSH before 10.6, a server can trigger directory traversal (causing files to be written to unintended locations) during a recursive copy operation.

In the Linux kernel, the following vulnerability has been resolved: net: l2tp: do not propagate multicast notification errors The tunnel create, tunnel modify, session create, and session modify netlink handlers send multicast notifications through helpers that can fail while allocating or encoding a message, or while multicasting it. For tunnel and session create/modify, a notification is sent after the live operation has completed. Returning a best-effort notification error as the command result can therefore report failure for an operation that already committed and can cause callers to retry and accumulate live objects. Keep sending notifications for listener visibility, but do not propagate their best-effort status as the command result. This also keeps the tunnel modify command consistent with the other notification-only paths.

A heap-based buffer overflow in VPN certificate ASN.1 decoding may allow an unauthenticated remote attacker to execute arbitrary code on Check Point Quantum Security Management and Quantum Security Gateway systems.

Improper certificate trust validation during VPN negotiation in Check Point Quantum Security Gateway may allow an unauthenticated remote attacker to execute arbitrary code on the Gateway.

Use after free in Windows Secure Socket Tunneling Protocol (SSTP) allows an unauthorized attacker to execute code over a network.

Use after free in Windows Secure Socket Tunneling Protocol (SSTP) allows an authorized attacker to execute code locally.

Use after free in Windows Secure Socket Tunneling Protocol (SSTP) allows an authorized attacker to elevate privileges locally.

RouterOS contains an argument-handling flaw in the SSH login path involving usernames that begin with a prohibited character, allowing for the trusted RouterOS policy mask to be changed, leading to privilege escalation. Exploitation requires an unauthenticated SSH session to reach the RouterOS login helper.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

RouterOS SSH enters the connection protocol after a client-requested rekey even though user authentication was never attempted, allowing an unauthenticated client to open a session channel and send an exec request. On affected builds the server dispatches the command, enabling unauthenticated creation, overwrite, and reconstruction of files in the RouterOS managed file namespace, including support files containing configuration and diagnostic data.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With "random-data=false", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel. This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

Zephyr's WireGuard VPN data-plane receive handler wg_process_data_message() in subsys/net/lib/wireguard/wg_crypto.c validated the anti-replay counter too late. After AEAD decryption of a MESSAGE_TRANSPORT_DATA packet succeeded, the code committed several peer-state changes — update_peer_addr() (endpoint roaming update), the keypair->last_rx/peer->last_rx liveness timers, and keypair_update() (promote next→current and destroy the previous keypair) — and only afterward called wg_check_replay(). On a replayed packet the replay check returned -EINVAL, but none of the preceding mutations were rolled back. The AEAD tag authenticates content but not freshness, so a replayed-but-authentic transport packet decrypts correctly. An attacker who captures one valid ciphertext off the wire (an on-path or shared-medium observer) can re-inject it from an arbitrary spoofed source address. Reaching the handler requires no credentials: it is driven directly from inbound UDP datagrams via the dispatch in subsys/net/lib/wireguard/wg.c. Because the state mutations committed before the replay check, the replay repoints the peer endpoint to the attacker-chosen source address (roaming hijack), redirecting the victim's subsequent outbound tunnel traffic until the legitimate peer's next packet re-corrects it; it also prematurely destroys the previous keypair and refreshes the RX liveness timer. The tunnel payload stays encrypted under the session keypair, so this is an integrity/availability impact (traffic redirection and session disruption), not payload disclosure. The fix moves wg_check_replay() to immediately after a successful decrypt, before any peer-state mutation, matching the WireGuard specification and the Linux reference implementation.

Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 0.3.9, the Logto Tunnel npm package enabled createStaticFileProxy from packages/tunnel/src/commands/tunnel/index.ts and passed request.url from static asset requests through packages/tunnel/src/commands/tunnel/utils.ts using path.join(staticPath, request.url) and then fs.open(requestPath, "r") without URL normalization or a containment check. When --experience-path was enabled and the tunnel port was reachable, an unauthenticated requester could send a path containing ../ to createStaticFileProxy and read files outside the configured static directory that were readable by the logto-tunnel process. The service used server.listen(port), which could expose the tunnel to other hosts depending on the platform and deployment. This issue is fixed in version 0.3.9.

OpenVPN 2.7_alpha1 through 2.7.5 using mbedTLS allows remote authenticated users to be misidentified by ignoring the configured X.509 username identity lookup field

The Windows interactive service in OpenVPN 2.4.0 through 2.6.21 and 2.7_alpha1 through 2.7.5 allows local authenticated users to bypass the trusted configuration directory constraint and load arbitrary configuration files via crafted options that bypass whitelist checks

In sshd in OpenSSH before 10.5, the restrict keyword (in authorized_keys) was supposed to be applicable to tunnel forwarding but was not.

In ssh in OpenSSH before 10.5, a use-after-free for realloc data can occur if a certain pair of remote-forwarding operations are concurrent.

In ssh-agent in OpenSSH before 10.5, some operations can occur remotely but were intended to occur only locally, including operations that add tokens or use keys. This is caused by misinteraction between agent locking and the session-bind@openssh.com extension.

Double free in Windows Secure Socket Tunneling Protocol (SSTP) allows an unauthorized attacker to execute code over a network.

The Windows interactive service in OpenVPN 2.7_alpha1 through 2.7.4 allows remote attackers to cause persistent DNS state pollution or a service crash via a crafted search domain during the disconnection process

A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry

An incomplete guard in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote authenticated peers to trigger a use-after-free during TLS session promotion, potentially leading to a denial of service or memory leakage

A memory leak in the tls-crypt-v2 client key extraction in OpenVPN 2.5.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers to cause a denial of service (memory exhaustion) via a flood of crafted packets

VeloCloud Orchestrator (VCO) on-prem has a security issue where this issue may allow a remote attacker to access privileged internal functionality and impact the VCO host. Successful exploitation may compromise the confidentiality, integrity, and availability of the orchestrator and data managed by the orchestrator. This functionality was intended to be for internal use only and is not intended to be remotely accessible. Hosted and Dedicated versions of VCO have already been patched in advance of this notice going out. This issue was discovered externally and is known to be actively exploited.

WireGuard Easy through 15.3.0, fixed in commit 66b292b, contains a cryptographically weak one-time link token generation vulnerability that allows unauthenticated network attackers to recover WireGuard peer credentials by brute-forcing a keyspace of at most 1000 candidate tokens per client ID, as the token is computed using CRC32 over a random value constrained to 0-999. Attackers can enumerate candidate tokens against the unauthenticated /cnf/:oneTimeLink route, which lacks rate limiting and does not validate token expiration, to obtain a peer's PrivateKey and PresharedKey and impersonate that peer on the VPN network.

Incorrect access of indexable resource ('range error') in Windows Sensor Data Service allows an authorized attacker to elevate privileges locally.

Use after free in Windows Secure Socket Tunneling Protocol (SSTP) allows an unauthorized attacker to execute code over a network.

ssh in OpenSSH before 10.4 can have a use-after-free when a server changes its host key during a key re-exchange. (This outcome occurs only on the client side.)

sshd in OpenSSH before 10.4 does not always honor the minimum authentication delay.

sshd in OpenSSH before 10.4 allows remote attackers to cause a denial of service (resource consumption from excessive authentication attempts) because MaxAuthTries was mishandled for GSSAPIAuthentication.

In sshd in OpenSSH before 10.4, DisableForwarding=yes was supposed to take precedence over PermitTunnel=yes, but did not.

sshd in OpenSSH before 10.4 has an undocumented security-relevant behavior: GSSAPIStrictAcceptorCheck has no value if the server is in Windows Active Directory.

internal-sftp in sshd in OpenSSH before 10.4 recognizes only the first 9 command-line arguments, which can be important if a later command-line argument would have helped to ensure the intended security properties of an SFTP connection.

scp in OpenSSH before 10.4 may place a file in the parent directory of an intended directory when the copy occurs between two remote destinations.

sftp in OpenSSH before 10.4 does not properly constrain the location of downloaded files when "sftp server:/path ." is used with an attacker-controlled server.

Incorrect authorization in the XML-RPC API of WebPros Plesk before 18.0.78.4 allows a low-privileged authenticated customer to look up domains they do not own, because ownership is enforced only for certain lookup filters and schema validation is bypassed for legacy protocol versions. This results in cross-tenant disclosure of other tenants' FTP credentials stored in cleartext, which can be leveraged to execute code as another tenant's system user.

OpenVPN version 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers to cause a denial of service via a malformed authentication token that triggers a reachable assertion when external-auth is enabled

A memory leak in OpenVPN version 2.5.0 through 2.5.11, 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers with a valid tls-crypt-v2 client key to potentially cause a denial of service

socat versions 1.8.0.0 through 1.8.1.1 contain a heap-based buffer overflow vulnerability that allows a malicious SOCKS5 proxy server to overwrite adjacent heap memory by exploiting a sign-extension flaw in the DOMAINNAME reply parser. During connection setup, the domain name length byte is read through a signed char field causing a negative bytes_to_read value that is implicitly converted to size_t, resulting in an unbounded heap write into the 262-byte reply buffer with attacker-controlled size and content.

In the Linux kernel, the following vulnerability has been resolved: Revert "wireguard: device: enable threaded NAPI" This reverts commit 933466fc50a8e4eb167acbd0d8ec96a078462e9c which is commit db9ae3b6b43c79b1ba87eea849fd65efa05b4b2e upstream. We have had three independent production user reports in combination with Cilium utilizing WireGuard as encryption underneath that k8s Pod E/W traffic to certain peer nodes fully stalled. The situation appears as follows: - Occurs very rarely but at random times under heavy networking load. - Once the issue triggers the decryption side stops working completely for that WireGuard peer, other peers keep working fine. The stall happens also for newly initiated connections towards that particular WireGuard peer. - Only the decryption side is affected, never the encryption side. - Once it triggers, it never recovers and remains in this state, the CPU/mem on that node looks normal, no leak, busy loop or crash. - bpftrace on the affected system shows that wg_prev_queue_enqueue fails, thus the MAX_QUEUED_PACKETS (1024 skbs!) for the peer's rx_queue is reached. - Also, bpftrace shows that wg_packet_rx_poll for that peer is never called again after reaching this state for that peer. For other peers wg_packet_rx_poll does get called normally. - Commit db9ae3b ("wireguard: device: enable threaded NAPI") switched WireGuard to threaded NAPI by default. The default has not been changed for triggering the issue, neither did CPU hotplugging occur (i.e. 5bd8de2 ("wireguard: queueing: always return valid online CPU in wg_cpumask_choose_online()")). - The issue has been observed with stable kernels of v5.15 as well as v6.1. It was reported to us that v5.10 stable is working fine, and no report on v6.6 stable either (somewhat related discussion in [0] though). - In the WireGuard driver the only material difference between v5.10 stable and v5.15 stable is the switch to threaded NAPI by default. [0] https://lore.kernel.org/netdev/CA+wXwBTT74RErDGAnj98PqS=wvdh8eM1pi4q6tTdExtjnokKqA@mail.gmail.com/ Breakdown of the problem: 1) skbs arriving for decryption are enqueued to the peer->rx_queue in wg_packet_consume_data via wg_queue_enqueue_per_device_and_peer. 2) The latter only moves the skb into the MPSC peer queue if it does not surpass MAX_QUEUED_PACKETS (1024) which is kept track in an atomic counter via wg_prev_queue_enqueue. 3) In case enqueueing was successful, the skb is also queued up in the device queue, round-robin picks a next online CPU, and schedules the decryption worker. 4) The wg_packet_decrypt_worker, once scheduled, picks these up from the queue, decrypts the packets and once done calls into wg_queue_enqueue_per_peer_rx. 5) The latter updates the state to PACKET_STATE_CRYPTED on success and calls napi_schedule on the per peer->napi instance. 6) NAPI then polls via wg_packet_rx_poll. wg_prev_queue_peek checks on the peer->rx_queue. It will wg_prev_queue_dequeue if the queue->peeked skb was not cached yet, or just return the latter otherwise. (wg_prev_queue_drop_peeked later clears the cache.) 7) From an ordering perspective, the peer->rx_queue has skbs in order while the device queue with the per-CPU worker threads from a global ordering PoV can finish the decryption and signal the skb PACKET_STATE_CRYPTED out of order. 8) A situation can be observed that the first packet coming in will be stuck waiting for the decryption worker to be scheduled for a longer time when the system is under pressure. 9) While this is the case, the other CPUs in the meantime finish decryption and call into napi_schedule. 10) Now in wg_packet_rx_poll it picks up the first in-order skb from the peer->rx_queue and sees that its state is still PACKET_STATE_UNCRYPTED. The NAPI poll routine then exits e ---truncated---

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker, under specific configurations involving GSSAPI authentication and a Kerberos environment, could exploit this to cause the SSH authentication path to crash or abort. This leads to a denial of service (DoS), impacting the availability of the SSH service.

A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).