CVE-2026-18353
JWT issuer parsing mismatch allows JWKS fetch to attacker host, enabling token forgery.
Is CVE-2026-18353 being exploited?
Not confirmed. CVE-2026-18353 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 0.24% probability of exploitation in the next 30 days.
How severe is CVE-2026-18353?
CVE-2026-18353 is rated High with a CVSS score of 8.8. 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-2026-18353?
Yes. A fix has been recorded for CVE-2026-18353. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-18353 affect?
CVE-2026-18353 affects PIA POST /v1/upload/sbom endpoint, Python OIDC implementations using urlparse + requests, Services that validate JWT 'iss' via urlparse allowlist. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-18353?
Apply vendor patch; normalize and strictly validate issuer URLs, reject backslashes, or hardcode JWKS endpoints.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Auth bypass / token forgery via SSRF: attacker drives JWKS retrieval to attacker-controlled host, enabling acceptance of forged JWTs and account impersonation.
Immediate action required
- affected>= 0.4.0 and < 0.6.0
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.