CVE-2026-63971 sctp: fix race between sctp_wait_for_connect and peeloff
A race condition in the Linux kernel SCTP implementation allows attackers to access memory under the wrong lock, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63971?
CVE-2026-63971 is a high-severity vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-362
Which versions are affected by CVE-2026-63971?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-63971?
Apply the vendor's patch.
Is CVE-2026-63971 being exploited?
There is no known exploitation of CVE-2026-63971 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-63971, DEBIAN-CVE-2026-63971, GHSA-p8fw-9cj8-hc3p, ROOT-OS-UBUNTU-2204-CVE-2026-63971, UBUNTU-CVE-2026-63971.