CVE-2026-63971 (CVSS 7.8)

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix race between sctp_wait_for_connect and peeloff sctp_wait_for_connect() drops and re-acquires the socket lock while waiting for the association to reach ESTABLISHED state. During this window, another thread can peeloff the association to a new socket via getsockopt(SCTP_SOCKOPT_PEELOFF), changing asoc->base.sk. After re-acquiring the old socket lock, sctp_wait_for_connect() returns success without noticing the migration — the caller then accesses the association under the wrong lock in sctp_datamsg_from_user(). Add the same sk != asoc->base.sk check that sctp_wait_for_sndbuf() already has, returning an error if the association was migrated while we slept.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0016

Probability of exploitation

0.06%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/0e0d5bc76fd4267a71334fcc8f1a5fbcf997845d https://git.kernel.org/stable/c/6140cfa721451fa6e18e134e709703c2bf34d0fb https://git.kernel.org/stable/c/634a9af8a26a84d8b0d7b3b643204b344b42d9fb https://git.kernel.org/stable/c/68667ee4c7dadf7f63167234e2a1af09b3f7874e https://git.kernel.org/stable/c/7d2038d4b80166f7bead8d07eba3b97405816c21 https://git.kernel.org/stable/c/8e9b56051d24540cfbf39194618708c4a7633549 https://git.kernel.org/stable/c/bcfeac79af740735ace44008b4a11b8e5add20f5 https://git.kernel.org/stable/c/f14fe6395a8b3d961a61e138ad7b36ba3626dd4e

Frequently Asked Questions

What is CVE-2026-63971? +

In the Linux kernel, the following vulnerability has been resolved: sctp: fix race between sctp_wait_for_connect and peeloff sctp_wait_for_connect() drops and re-acquires the socket lock while waiting for the association to reach ESTABLISHED state. During this window, another thread can peeloff the association to a new socket via getsockopt(SCTP_SOCKOPT_PEELOFF), changing asoc->base.sk. After re-acquiring the old socket lock, sctp_wait_for_connect() returns success without noticing the migration — the caller then accesses the association under the wrong lock in sctp_datamsg_from_user(). Add the same sk != asoc->base.sk check that sctp_wait_for_sndbuf() already has, returning an error if the association was migrated while we slept. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-63971? +

CVE-2026-63971 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0016, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-63971? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-63971