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VulnerabilityPublished Updated

CVE-2026-101307: FreeBSD · Heap-based Buffer Overflow

Affects FreeBSDSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to p5 soon.

Data as of 9 Nov 2026, 14:34 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CISA-ADPCVSS 4.08.2
CISA-ADPCVSS 3.15.9
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-15.

Patch
Available – fixed in p5
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Upgrade FreeBSD to p5.

Affected software

ProductAffectedFixed in
FreeBSDFreeBSDAffected
  • >=15.1-RELEASE <p5
Fixed in
  • p5

AI-suggested

A fix is available in FreeBSD version p5. Users should upgrade to this fixed version to remediate the vulnerability. No other mitigation or workaround is specified.

Description

CVE-2026-101307 is a heap-based buffer overflow vulnerability in the FreeBSD RACK TCP stack. The issue arises when the PCM sample array grows by doubling a 16-bit allocation counter, which can wrap to zero after repeated doublings. This leads to an undersized buffer allocation and a subsequent out-of-bounds write in kernel memory. A remote attacker can trigger this by sending many ACKs on an established TCP connection, potentially causing a kernel panic.

References

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