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Remotely triggerable buffer overflow in tcp_rack

FreeBSD · CVE-2026-101307
0 news outlets1 CERTs and agencies0 researchers

What is it?

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.

Evidence

CERTs and agencies (1)

Exploitation

  • Public proof of concept
  • Exploited in the wild
  • Listed as known exploited
CVSS
8.2
EPSS
0.3%
First seen
14 h ago
Status
confirmed

All FreeBSD vulnerabilities