01 Record
CVE-2026-55536
Browser Server WebSocket origin validation bypass via unanchored regex (patch bypass of CVE-2026-40289 / GHSA-8x8f-54wf-vv92)
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
Browser Server WebSocket origin validation bypass via unanchored regex (patch bypass of CVE-2026-40289 / GHSA-8x8f-54wf-vv92)
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.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 0.52% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 43.9% 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 2026-09-09.
- 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
- 2026-08-25 15:21Z2 MO AGO
- Last updated
- 2026-08-28 22:27Z2 MO AGO
- Reserved
- 2026-06-16
- 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
- Data version
- 5.2
- Document digest
- 7ae13d0070eed65d394517bcab899640d9c947878f04e49c8f9f4b056ffd5f90
05 Affected products
VendorProductVersionsPlatforms