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VulnerabilityPublished

CVE-2026-42919: F5 BIG-IP · Stack-based Buffer Overflow

Affects F5 BIG-IPSource CVE Database V5

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Not known to be exploited · CVSS 6.7 Medium · fixed in 21.0.0.1 : update F5 BIG-IP when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score
6.7Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 21.0.0.1, 17.5.1.4, 17.1.3.1
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 May 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 29 Oct 2026.

What to do

Upgrade F5 BIG-IP to 21.0.0.1, 17.5.1.4 or 17.1.3.1.

Affected software

ProductAffectedFixed in
F5BIG-IPAffected
  • >=21.0.0 <21.0.0.1
  • >=17.5.0 <17.5.1.4
  • >=17.1.0 <17.1.3.1
  • >=16.1.0
Fixed in
  • 21.0.0.1
  • 17.5.1.4
  • 17.1.3.1

AI-suggested

If you cannot patch yet, organizations should limit administrative access to trusted personnel only and monitor for unusual administrative activity. No vendor advisory or patch links are currently available, so follow F5's official channels for updates.

Description

CVE-2026-42919 is a stack-based buffer overflow vulnerability in F5 BIG-IP systems. It affects multiple versions including 21.0.0, 17.5.0, 17.1.0, and 16.1.0.

References

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