CVE-2026-49422Use-after-free in TCP RACK stack option handler
Updated under an hour ago ()
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It affects FreeBSD. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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The RACK setsockopt(2) handler drops the connection lock in order to copy option data from userspace, then reacquires the lock. After reacquiring, it verifies that the TCP stack had not been switched away, but did not reload its pointer to the stack's per-connection control block. If userspace switches stacks twice during this window, the check will succeed but the saved pointer will refer to freed memory. The bug may be exploitable by an unprivileged local user to escalate privileges.
- CVSS
- 8.4 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-416
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- freebsd
- NVD analysis
- Analyzed
- Record last updated
- Aug 20, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
FreeBSD FreeBSD freebsd:freebsd (from the name) | from 15.1-RELEASE before p1; from 15.0-RELEASE before p11; from 14.4-RELEASE before p7; from 14.3-RELEASE before p16 | CNA record |
freebsd freebsd freebsd:freebsd | 14.3; 14.3; 14.3; 14.3; 14.3; 14.3; 14.3; 14.3; and 30 more ranges | NVD |
References
- https://security.freebsd.org/advisories/FreeBSD-SA-26:43.tcp.ascvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.