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VulnerabilityPublished

CVE-2026-58087: FreeBSD · Integer Underflow

Affects FreeBSDSource GCVE Database

0

Not known to be exploited · CVSS 7.8 High.

Data as of 27 Oct 2026, 14:14 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: 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 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
FreeBSD FreeBSDAffected
  • =15.1-RELEASE
  • =15.0-RELEASE
  • =14.4-RELEASE
Fixed in–

AI-suggested

Until a patch is available, restrict unprivileged local user access where possible to mitigate exploitation risk.

Description

CVE-2026-58087 is an integer underflow vulnerability in FreeBSD's semctl(2) system call affecting the GETALL and SETALL commands. The flaw arises due to sequence number wrapping after 0x8000 create/destroy cycles of semaphore sets, allowing an attacker to bypass validation and cause out-of-bounds reads and writes on kernel heap memory. This can be exploited by an unprivileged local user to potentially escalate privileges. The vulnerability affects FreeBSD versions 14.4-RELEASE, 15.0-RELEASE, and 15.1-RELEASE. It has a high severity rating with a CVSS score of 7.8. No patch information is provided in the input data.

References

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