CVE-2026-43500

Published May 11, 2026

Last updated a month ago

CVSS high 7.8

Ubuntu

Container Security

Server

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-43500 is a vulnerability found within the Linux kernel's RxRPC networking subsystem, forming one half of a pair of flaws collectively dubbed "Dirty Frag." This issue arises when a non-linear socket buffer, which carries a splice-pinned page-cache reference, reaches the RxRPC authentication verification path. Instead of isolating the buffer, the kernel performs an in-place decryption directly on the referenced page-cache page. This behavior can be exploited by an unprivileged local attacker to corrupt the contents of the page-cache. By manipulating cached data in memory, an attacker could potentially overwrite sensitive system files, such as `/etc/passwd`, to achieve unauthorized access or escalate privileges.

Description: 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.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status: Modified
Products: linux_kernel

Risk scores

CVSS 3.1

Type: Primary
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

Weaknesses

nvd@nist.gov: CWE-787
134c704f-9b21-4f2e-91b3-4a467353bcc0: CWE-787

Hype score: Not currently trending

Configurations

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References

Sources include official advisories and independent security research.