CVE-2026-101307: FreeBSD · Heap-based Buffer Overflow
Affects FreeBSDSource CVE Database V5
Not known to be exploited · CVSS 8.2 High : upgrade to p5 soon.
Data as of 9 Nov 2026, 14:34 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 4.0 | 8.2 |
|---|---|---|
| CISA-ADP | CVSS 3.1 | 5.9 |
- 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:NExploitation evidence
Disclosed: evidence found.
CVE published 15 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| FreeBSDFreeBSD | Affected
| Fixed in
|
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.