CVE-2026-34840CWE-347

CVE-2026-34840

High · published April 3, 2026

CVSS v3.1
8.1
EPSS
0%
Percentile
26.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.1 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00343 · 26.6th percentile
Weakness
CWE-347 · Improper Verification of Cryptographic Signature
Published
2026-04-03T00:16Z
Affected products (1)
ProductVersionsFixed in
hackerbay/oneuptime< 10.0.4210.0.42
References (3)
EPSS history
Timeline
  • 02 APR 18:52Z
    OneUptime SSO: Multi-Assertion Identity Injection via Decoupled Signature Verification
    cvelistv5