CVE-2026-53424
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| dropbox | samly | 0.3.0 < * | affected |
| dropbox | samly | 8a5bb1b4a4753d05470da2036323477f63cfdf4c < * | affected |
| handnot2 | samly | 8a5bb1b4a4753d05470da2036323477f63cfdf4c < * | affected |
Weaknesses
- CWE-294: CWE-294 Authentication Bypass by Capture-replay
References
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