When the PCM sample array needs to grow, the RACK stack doubles a 16-bit allocation counter. Repeated doublings caused the counter to wrap to zero, resulting in a near-zero-length allocation followed by a copy of the existing samples into the undersized buffer. A remote peer can trigger the expansion by sending a sufficient number of ACKs on an established connection. A remote attacker who can establish a TCP connection to a system using the RACK stack can trigger an out-of-bounds write of approximately 512 KB in the kernel heap possibly resulting in a kernel panic.
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://security.freebsd.org/advisories/FreeBSD-SA-26:70.tcp.asc Mitigation, Patch, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 7
- Cpes+5 CPE criteria (now 5)NVD modified 2026-10-20 00:21
- StatusUndergoing Analysis → AnalyzedNVD modified 2026-10-20 00:21
- StatusAwaiting Analysis → Undergoing AnalysisNVD modified 2026-10-15 17:17
- CVSS6.5 (v3.1, CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) → 8.2 (v4.0, CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)NVD modified 2026-10-15 17:17
- StatusReceived → Awaiting AnalysisNVD modified 2026-10-15 16:17
- CVSS6.5 (v3.1, CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)NVD modified 2026-10-15 16:17
- First seenunscoredNVD modified 2026-10-15 07:17
Affected (CPE criteria) 5
cpe:2.3:o:freebsd:freebsd:15.1:-:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.1:p1:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.1:p2:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.1:p3:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.1:p4:*:*:*:*:*:*
References 1
- https://security.freebsd.org/advisories/FreeBSD-SA-26:70.tcp.asc Mitigation, Patch, Vendor Advisory