What’s Vulnerable › Vulnerabilities

CVE-2026-74436: rxrpc: serialize kernel accept preallocation with socket teardown

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-15 · updated 2026-10-16

Description

In the Linux kernel, the following vulnerability has been resolved: rxrpc: serialize kernel accept preallocation with socket teardown rxrpc_kernel_charge_accept() reads rx->backlog without any socket/backlog synchronization and passes that raw pointer into rxrpc_service_prealloc_one(). A concurrent rxrpc_discard_prealloc() sets rx->backlog = NULL and frees the backlog rings, so a kernel preallocation worker can keep using a freed struct rxrpc_backlog while updating *_backlog_head/tail and array slots. Serialize the state check and backlog lookup with the socket lock, and reject kernel preallocation once teardown has disabled listening or discarded the service backlog.

Affected products

• Linux kernel: 4.9 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0337cdba0c477f176c0459bed012109453184573
• https://git.kernel.org/stable/c/11b429b84c87cb5a0152f14e7d6cb649ed363901
• https://git.kernel.org/stable/c/1741378a7a83dfd8e53a9196730df709b903cd33
• https://git.kernel.org/stable/c/35a967ff8b24db09ee429c39c5b5e6571639997d
• https://git.kernel.org/stable/c/c20d983968f239574290cf804a58cde18ad1c559
• https://git.kernel.org/stable/c/d6207326b4ca0ae1041281b6af9df53f8080669a
• https://git.kernel.org/stable/c/dc175389b18c29a5303ee83169ec653adfae3e17
• https://git.kernel.org/stable/c/dfa0b2bbc5e50119f89c6b5407faa5ed86dfa7c5

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