CVE-2026-53424
SAML replay allows authentication bypass in samly (Elixir) via reusable SAMLResponse.
Is CVE-2026-53424 being exploited?
Not confirmed. CVE-2026-53424 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 0.34% probability of exploitation in the next 30 days.
How severe is CVE-2026-53424?
CVE-2026-53424 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-2026-53424?
Not known from our data. No patch reference has been recorded for CVE-2026-53424, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-53424 affect?
CVE-2026-53424 affects samly (Dropbox) >= 0.3.0, Elixir/Phoenix apps using samly for SAML SSO. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-53424?
Disable samly SSO or block replay, enforce IdP duplicate-detection, rotate sessions, apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers can replay captured SAMLResponse to authenticate as the assertion subject until assertion expiry, gaining account access.
Immediate action required
- affected>= 0.3.0 and < *
- affected>= 8a5bb1b4a4753d05470da2036323477f63cfdf4c and < *
- affected>= 8a5bb1b4a4753d05470da2036323477f63cfdf4c and < *
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.