Vulnerability details

CVE-2026-88007

traefik traefik

Traefik HTTP/3 Backend NTLM Connection Reuse

CVSS 4.0
9.1Critical

Official description

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.0 until 2.11.57 and 3.7.13, the HTTP/3 entrypoint ConnContext does not call service.AddTransportOnContext, so kerberosRoundTripper uses a shared backend transport instead of a transport dedicated to each frontend connection. With HTTP/3 enabled, a backend using connection-bound NTLM or Negotiate authentication, and backend keep-alive, an unrelated client can reuse a backend connection authenticated for a victim, read victim-only data, and act as that victim without the victim credentials. This issue is fixed in 2.11.57 and 3.7.13.

CVSS scores

ScoreVersionSourceVector
9.1Critical 4.0 CVEProject cvelistV5 (CNA) (GitHub_M) CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Affected products

VendorProductVersionsSource
traefik traefik >= 2.11.0, < 2.11.57 CVEProject cvelistV5 (CNA)
traefik traefik >= 3.0.0, < 3.7.13 CVEProject cvelistV5 (CNA)

References and advisories

5
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Details

Published
2026-09-10
Last updated
2026-09-10
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.6%
Probability of exploitation in 30 days
48.9%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
None
Technical impact
Total

Weaknesses (CWE)

  • CWE-287
    Improper Authentication
  • CWE-863
    Incorrect Authorization