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Denial of service in Perl CGI::Cookie through crafted expires value

Priority LOW 23CWE-1333Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
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Impact type
Denial of service
Confidentiality · integrity · availability
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Fix status
Partial Red Hat: 4 without a fix

No CVSS vector from any source. Fix status from CNA and Red Hat. Impact type from CWE-1333.

Summary

CGI::Cookie for Perl from 4.67 before 5.00 is affected. The parse function inserts the cookie's expires value unescaped into a regex, so a crafted value causes an invalid pattern or excessive backtracking (CWE-1333). A client can send a crafted Cookie header that makes the request die or ties up the process, causing denial of service.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

CGI::Cookie versions from 4.67 before 5.00 for Perl allow denial of service via the client cookie expires value used as a regex in parse. CGI's cookie method reads the Cookie request header through parse, which interpolates the header's expires value unescaped into the substitution pattern that removes it from the cookie string. A client can make the request die with an invalid pattern, or tie up the process with one that backtracks catastrophically.

Why it matters now

EPSS 0.00389 33rd percentileScored 2026-11-07
Fix Partial CGI: 5.00Red Hat: 4 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—CGI4.67 to before 5.005.00Patch availableCNA
  • CGI Vendor— Affected 4.67 to before 5.00 Fixed in 5.00 Patch available CNA

Remediation

Update CGI to version 5.00, which fixes the flaw. Red Hat Enterprise Linux 7, 8, 9 and 10 are affected, and the sources list no fixed version for them.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

  • Fix · CNA CGI Fixed in 5.00

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 7AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet

Timeline

  1. 2026-11-03 Threatist record created from CVE-2026-120631
  2. 2026-11-04 Affected versions changed · Red Hat
  3. 2026-11-04 CVSS score added · Red Hat
  4. 2026-11-04 Alias added: GHSA-v4gh-jwmf-g38j

References

Sources