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TI-2026-26336 Aliases CVE-2026-33996

LibJWT has NULL/bounds validation in JWK octet and RSA PSS parsing

Priority LOW 25CWE-476Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
Active
Attack complexity
High
Attack requirements
Present
Impact type
Denial of service
Confidentiality · integrity · availability
Low · Low · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-476.

Summary

LibJWT is a C JSON Web Token Library. Starting in version 3.0.0 and prior to version 3.3.0, the JWK parsing for RSA-PSS did not protect against a NULL value when expecting to parse JSON string values. A specially crafted JWK file could exploit this behavior by using integers in places where the code expected a string. This was fixed in v3.3.0. A workaround is available. Users importing keys through a JWK file should not do so from untrusted sources. Use the `jwk2key` tool to check for validity of a JWK file. Likewise, if possible, do not use JWK files with RSA-PSS keys.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00158 4th percentileScored 2026-11-07
Fix Fixed libjwt (benmcollins): 3.3.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
benmcollinslibjwt3.0.0 to before 3.3.03.3.0Patch availableCNA
  • libjwt Vendorbenmcollins Affected 3.0.0 to before 3.3.0 Fixed in 3.3.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:libjwt:libjwt:*:*:*:*:*:*:*:*3.0.0 to before 3.3.0VulnerableLibjwt
  • cpe:2.3:a:libjwt:libjwt:*:*:*:*:*:*:*:* Versions 3.0.0 to before 3.3.0 Vulnerable ·Libjwt

Remediation

  • Fix · CNA libjwt (benmcollins) Fixed in 3.3.0

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33996

References

Patch 1

Advisory 1

  • TI-2026-32590 LibJWT: Algorithm confusion allows JWT forgery with RSA JWK as empty-key HMAC CVSS 4.0CRITICAL 9.1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences