CVE-2026-53424 Details
Description
Authentication Bypass by Capture-replay vulnerability in dropbox samly allows an attacker to authenticate as the subject of a captured SAML assertion by resubmitting it. Samly.Helper.decode_idp_auth_resp/3 in lib/samly/helper.ex calls esaml_sp:validate_assertion/2, whose default duplicate detector is a no-op. The /3 arity accepting a DuplicateFun exists in esaml and implements the check, but Samly never calls it and offers no configuration to supply one, so the SAML 2.0 Web Browser SSO Profile requirement that a bearer assertion be used once is unenforced. An attacker holding a valid SAMLResponse obtained from the network, from browser history, or from logs can submit the identical bytes repeatedly until the assertion's NotOnOrAfter passes, each time establishing a session as the assertion's subject. This issue affects samly: from 0.3.0 onward.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No CVSS 3.x data is available for this CVE.
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Aug 21, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://cna.erlef.org/cves/CVE-2026-53424.html | EEF | |
| https://osv.dev/vulnerability/EEF-CVE-2026-53424 | EEF |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-294 | Authentication Bypass by Capture-replay | EEF |
Affected Products
No affected product data is available for this CVE.
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 21, 2026 | CVE Modified | CISA-ADP |
| Aug 20, 2026 | CVE Modified | EEF |
| Aug 20, 2026 | New CVE Received | EEF |