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VulnerabilityPublished

CVE-2026-120635: CGI versions before 5.00 for Perl allow form fields to be smuggled past proxies and WAFs via

Source GCVE Database

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Authoritative record:CVE-2026-120635· High

Not known to be exploited : upgrade to 5.00 soon.

Data as of 4 Nov 2026, 02:00 UTC

Severity
High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none
Patch
Available – fixed in 5.00

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Nov 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 3 Nov 2026.

What to do

Upgrade CGI (Perl module) to 5.00.

Affected software

ProductAffectedFixed in
CGIAffected
  • <5.00
Fixed in
  • 5.00
CPANCGIpkg:cpan/CGIOther threatsAffected
  • <5.00
Fixed in
  • 5.00

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, users should consider additional protective measures at the network or application level to detect or block malformed multipart/form-data requests.

Description

CGI versions before 5.00 for Perl contain a vulnerability in their multipart/form-data parser that allows form fields to be smuggled past proxies and web application firewalls (WAFs). This occurs because the parser matches boundaries incorrectly, uses boundaries without the leading '--' for certain User-Agent values, misinterprets Content-Disposition parameters, and corrupts parts near the 4096-byte read size.

References

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