High 8.1Published Apr 2, 2026

CVE-2026-34840OneUptime SSO: Multi-Assertion Identity Injection via Decoupled Signature Verification

Updated under an hour ago (Oct 26, 2026, 4:10 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.42, OneUptime's SAML SSO implementation (App/FeatureSet/Identity/Utils/SSO.ts) has decoupled signature verification and identity extraction. isSignatureValid() verifies the first <Signature> element in the XML DOM using xml-crypto, while getEmail() always reads from assertion[0] via xml2js. An attacker can prepend an unsigned assertion containing an arbitrary identity before a legitimately signed assertion, resulting in authentication bypass. This issue has been patched in version 10.0.42.

CVSS: 8.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-347
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Apr 2, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

OneUptime oneuptime oneuptime:oneuptime (from the name)	before 10.0.42	CNA record
hackerbay oneuptime hackerbay:oneuptime	before 10.0.42	NVD

References

https://github.com/OneUptime/oneuptime/security/advisories/GHSA-5w5c-766x-265gx-refsource-confirm, exploit, mitigation, vendor-advisory
https://github.com/OneUptime/oneuptime/commit/2fd7ede52f60444710628d6c1b34dee2ef9e57d1x-refsource-misc, patch
https://github.com/OneUptime/oneuptime/releases/tag/10.0.42x-refsource-misc, product, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.