CVE-2026-18108
Auth bypass in Net::SAML2 (Perl) via unsigned decrypted EncryptedAssertion.
Is CVE-2026-18108 being exploited?
Not confirmed. CVE-2026-18108 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 0.22% probability of exploitation in the next 30 days.
How severe is CVE-2026-18108?
CVE-2026-18108 is rated Critical. 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-2026-18108?
Yes. A fix has been recorded for CVE-2026-18108. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-18108 affect?
CVE-2026-18108 affects Net::SAML2 < 0.86 (Perl module), Perl-based SAML Service Providers using decryption key_file, Applications using Net::SAML2 for SSO. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-18108?
Upgrade Net::SAML2 to >=0.86 or disable accepting/decrypting unsigned EncryptedAssertions.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attacker can send an encrypted, unsigned SAML assertion to impersonate arbitrary users and bypass SP authentication when decryption is enabled.
Immediate action required
- affected< 0.86
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.