Paper/Archive/CVE-2026-101307

CVE-2026-101307

FreeBSD FreeBSD — Remotely triggerable buffer overflow in tcp_rack

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
FreeBSD15.1-RELEASE – < p5p5CNA

Scores by source

NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CISA ADP8.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial

References

advisorysecurity.freebsd.org/advisories/FreeBSD-SA-26:70.tcp.asc