CVE-2025-38616: tls: handle data disappearing from under the TLS ULP

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-08-22 · updated 2026-08-27
Weakness: CWE-125

Description

In the Linux kernel, the following vulnerability has been resolved: tls: handle data disappearing from under the TLS ULP TLS expects that it owns the receive queue of the TCP socket. This cannot be guaranteed in case the reader of the TCP socket entered before the TLS ULP was installed, or uses some non-standard read API (eg. zerocopy ones). Replace the WARN_ON() and a buggy early exit (which leaves anchor pointing to a freed skb) with real error handling. Wipe the parsing state and tell the reader to retry. We already reload the anchor every time we (re)acquire the socket lock, so the only condition we need to avoid is an out of bounds read (not having enough bytes in the socket for previously parsed record len). If some data was read from under TLS but there's enough in the queue we'll reload and decrypt what is most likely not a valid TLS record. Leading to some undefined behavior from TLS perspective (corrupting a stream? missing an alert? missing an attack?) but no kernel crash should take place.

Affected products

Linux kernel: from 6.0 before 6.6.103; from 6.7 before 6.12.43; from 6.13 before 6.15.11; from 6.16 before 6.16.2; 6.17-rc1 — fixed in 6.12.43, 6.15.11, 6.16.2, 6.6.103

How to fix

Upgrade to a fixed version: Linux kernel 6.12.43, 6.15.11, 6.16.2, 6.6.103. Check the vendor advisory for mitigations.

References

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