CVE-2026-34840HIGH 8.1EPSS p17.6%

CVE-2026-34840CVE-2026-34840

Description

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.

Scoring

CVSS 3.18.1 (HIGH)
VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS0.26% probability of exploitation · percentile 17.6% · 2026-06-19T12:03:05Z
Published2026-04-02
Last modified2026-04-13

Underlying weaknesses· 1

CWE-347

References

  1. https://github.com/OneUptime/oneuptime/commit/2fd7ede52f60444710628d6c1b34dee2ef9e57d1
  2. https://github.com/OneUptime/oneuptime/releases/tag/10.0.42
  3. https://github.com/OneUptime/oneuptime/security/advisories/GHSA-5w5c-766x-265g

1

TypeTargetConfidenceTier
WeaknessImproper Verification of Cryptographic Signaturecwe-3470%live

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.