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
| Score | Version | Source | Vector |
|---|---|---|---|
| 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
| Vendor | Product | Versions | Source |
|---|---|---|---|
| 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- https://github.com/traefik/traefik/security/advisories/GHSA-qqjf-53cj-pwvv x_refsource_CONFIRM
- https://github.com/traefik/traefik/pull/13812 x_refsource_MISC
- https://github.com/traefik/traefik/commit/ff39c47d7459dec9cd8de63c1a4e7aa7315bdc1c x_refsource_MISC
- https://github.com/traefik/traefik/releases/tag/v2.11.57 x_refsource_MISC
- https://github.com/traefik/traefik/releases/tag/v3.7.13 x_refsource_MISC
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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-287Improper Authentication
- CWE-863Incorrect Authorization