CVE-2026-31431

Published Apr 22, 2026

Last updated 14 hours ago

Exploit knownCVSS high 7.8
Linux Kernel
Ubuntu
SSH
Amazon Redshift
Cloud
Container Security
Tunneling protocol
Port (22)
Tls
algif_aead

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-31431, dubbed "Copy Fail," is a local privilege escalation (LPE) vulnerability found within the Linux kernel's cryptographic subsystem. Specifically, it stems from a logic flaw in the `algif_aead` module of the `AF_ALG` (userspace crypto API), which leads to improper memory handling during in-place operations. This flaw allows an unprivileged local user to perform a deterministic, controlled 4-byte write into the page cache of any readable file on the system, including setuid binaries. This vulnerability has been present in Linux kernels since 2017 and impacts a wide range of major distributions, including Red Hat, SUSE, Ubuntu, and Amazon Linux. Exploitation is described as reliable, not requiring race conditions or kernel-specific offsets, and can be achieved with a small Python script. The in-memory corruption means the file on disk remains unchanged, and typical on-disk checksums would not detect the modification.

Description
In the Linux kernel, the following vulnerability has been resolved: crypto: algif_aead - Revert to operating out-of-place This mostly reverts commit 72548b093ee3 except for the copying of the associated data. There is no benefit in operating in-place in algif_aead since the source and destination come from different mappings. Get rid of all the complexity added for in-place operation and just copy the AD directly.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel, openshift_container_platform, enterprise_linux, amazon_linux, ubuntu_linux, debian_linux, leap, caas_platform, enterprise_storage, manager_proxy, manager_retail_branch_server, manager_server, openstack_cloud, openstack_cloud_crowbar, basesystem_module, development_tools_module, legacy_module, linux_enterprise_desktop, linux_enterprise_high_availability_extension, linux_enterprise_high_performance_computing, linux_enterprise_live_patching, linux_enterprise_micro, linux_enterprise_real_time, linux_enterprise_server, linux_enterprise_workstation_extension, linux_micro, public_cloud_module, realtime_module

Risk scores

CVSS 3.1

Type
Secondary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Known exploits

Data from CISA

Vulnerability name
Linux Kernel Incorrect Resource Transfer Between Spheres Vulnerability
Exploit added on
May 1, 2026
Exploit action due
May 15, 2026
Required action
"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Weaknesses

134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-669

Social media

Hype score
Not currently trending

  1. #exploit 1⃣ CVE-2026-31431: Code exec into containers sharing the same image layer https://t.co/1WHHD88uAH 2⃣ CVE-2025-68670: RCE in the xrdp server https://t.co/X8AYExy9VJ 3⃣ CVE-2026-23918: Apache mod_http2 vulnerability https://t.co/pBdyEHb0GL // Disclaimer

    @ksg93rd

    11 May 2026

    235 Impressions

    0 Retweets

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  2. CVE-2022-21894 CVE-2024-36877..... drum roll CVE-2026-31431 !!!

    @TomasRisov

    7 May 2026

    55 Impressions

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  3. #CopyFail (CVE-2026-31431) 🔓 9 ans incognito dans le noyau #Linux ! Accès root local sans compétence technique. Ubuntu, RHEL, SUSE, Amazon Linux 2023 concernés. ✅ Patch dispo depuis le 01/04/26 ✅ Ou désactiver algif_aead #Cybersécurité #SysAdmin https://t.co/2VOpZ

    @capensis_sas

    4 May 2026

    149 Impressions

    0 Retweets

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  4. Top 5 Trending CVEs: 1 - CVE-2026-31431 2 - CVE-2026-41940 3 - CVE-2026-3910 4 - CVE-2024-20359 5 - CVE-2024-20353 #cve #cvetrends #cveshield #cybersecurity https://t.co/4Fua3CAN6W

    @CVEShield

    3 May 2026

    120 Impressions

    0 Retweets

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  5. Top 5 Trending CVEs: 1 - CVE-2026-31431 2 - CVE-2021-3156 3 - CVE-2025-14847 4 - CVE-2024-27867 5 - CVE-2024-11182 #cve #cvetrends #cveshield #cybersecurity https://t.co/4Fua3CAN6W

    @CVEShield

    2 May 2026

    187 Impressions

    0 Retweets

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  6. 🔴 CVE-2026-31431 (High) affects Linux vendors: In the Linux kernel, the following vulnerability has been resolved: ✅ HAS FIX: Debian 14 Echo ❌ NO FIX YET: AlmaLinux 9 Alpine (all versions) Amazon Linux 2, 2023 Debian 11, 12, 13 Fedora (all versions) Oracle Linux 5-10 Re

    @MeniTasa

    1 May 2026

    1 Impression

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  7. 🚨 Critical Linux Kernel Vulnerability: CVE-2026-31431 (“Copy Fail”) A 732-byte Python script → root access on most Linux distros since 2017. Impact Works on: Ubuntu 24.04, Amazon Linux 2023, RHEL 10.1, SUSE 16 Discovered by Taeyang Lee at Theori using Xint Code #Linu

    @cveplayground

    30 Apr 2026

    1 Impression

    0 Retweets

    1 Like

    0 Bookmarks

    1 Reply

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Configurations

Related CVEs

  1. CVE-2025-14269
  2. In the Linux kernel, the following vulnerability has been resolved: rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owned paged fragments (e.g. SKBFL_SHARED_FRAG set by splice() into a UDP socket via __ip_append_data, or a chained skb_has_frag_list()) falls through to the in-place decryption path, which binds the frag pages directly into the AEAD/skcipher SGL via skb_to_sgvec(). Extend the gate to also unshare when skb_has_frag_list() or skb_has_shared_frag() is true. This catches the splice-loopback vector and other externally-shared frag sources while preserving the zero-copy fast path for skbs whose frags are kernel-private (e.g. NIC page_pool RX, GRO). The OOM/trace handling already in place is reused.•CVE-2026-43500
  3. In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data().•CVE-2026-43284
  4. In the Linux kernel, the following vulnerability has been resolved: net: ethernet: ec_bhf: Fix dma_free_coherent() dma handle dma_free_coherent() in error path takes priv->rx_buf.alloc_len as the dma handle. This would lead to improper unmapping of the buffer. Change the dma handle to priv->rx_buf.alloc_phys.•CVE-2026-43283
  5. In the Linux kernel, the following vulnerability has been resolved: RDMA/ionic: Fix potential NULL pointer dereference in ionic_query_port The function ionic_query_port() calls ib_device_get_netdev() without checking the return value which could lead to NULL pointer dereference, Fix it by checking the return value and return -ENODEV if the 'ndev' is NULL.•CVE-2026-43282

References

Sources include official advisories and independent security research.