CVE-2026-31676: rxrpc: only handle RESPONSE during service challenge

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-25 · updated 2026-10-19
Weakness: CWE-362

Description

In the Linux kernel, the following vulnerability has been resolved: rxrpc: only handle RESPONSE during service challenge Only process RESPONSE packets while the service connection is still in RXRPC_CONN_SERVICE_CHALLENGING. Check that state under state_lock before running response verification and security initialization, then use a local secured flag to decide whether to queue the secured-connection work after the state transition. This keeps duplicate or late RESPONSE packets from re-running the setup path and removes the unlocked post-transition state test.

Affected products

Linux kernel: from 2.6.22 before 6.6.136; from 6.7 before 6.12.84; from 6.13 before 6.18.23; from 6.19 before 6.19.13; 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5, 7.0-rc6 (+1) — fixed in 6.12.84, 6.18.23, 6.19.13, 6.6.136

How to fix

Upgrade to a fixed version: Linux kernel 6.12.84, 6.18.23, 6.19.13, 6.6.136. Check the vendor advisory for mitigations.

References

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