Widely used LibJWT library; critical auth bypass via JWT forgery; urgent remediation.
CVE-2026-44699
JWT forgery via missing alg in RSA JWK verification.
Is CVE-2026-44699 being exploited?
Not confirmed. CVE-2026-44699 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.21% probability of exploitation in the next 30 days.
How severe is CVE-2026-44699?
CVE-2026-44699 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-44699?
Yes. A fix has been recorded for CVE-2026-44699. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-44699 affect?
CVE-2026-44699 affects LibJWT 3.0.0-3.3.2, Apps loading RSA JWKS with missing alg in JWK, LibJWT-based JWT verification in user auth flows. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-44699?
Upgrade to 3.3.3; ensure alg is required in JWKS
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers forge valid JWTs without secrets/keys by omitting alg; bypasses authentication.
Immediate action required
- affected>= 3.0.0 and < 3.3.3
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.