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01 Record

CVE-2026-42889

Relay Server WebSocket authentication bypass when token is omitted

CriticalPUBLISHEDCNA: GitHub_M
CNA base score9.1 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

02 Description

Relay Server WebSocket authentication bypass when token is omitted

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.36% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 30.2% of scored records. A rank, not a probability.
NVD base score
9.1 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD analysis status
Deferred. NVD last modified this record on 2026-10-26.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-05-12 19:30Z5 MO AGO
Last updated
2026-05-13 12:32Z5 MO AGO
Reserved
2026-04-30
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
Critical (CVSS 9.1)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weaknesses
  • CWE-639Authorization Bypass Through User-Controlled KeyBase
  • CWE-863Incorrect AuthorizationClass
Data version
5.2
Document digest
89e8d639db13fdcad2d172758324aeb6da5f8d8e59506d58e20e9aef0b7a2230

05 Affected products

VendorProductVersionsPlatforms
No-Instructionsrelay-server>= 0.9.0, < 0.9.7—

06 References