Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing TLS handshake on TCP routers. When Traefik processes a TLS connection on a TCP router, the read deadline used to bound protocol sniffing is cleared before the TLS handshake is completed. When a TLS handshake read error occurs, the code attempts a second handshake with different connection parameters, silently ignoring the initial error. A remote unauthenticated client can exploit this by sending an incomplete TLS record and stopping further data transmission, causing the TLS handshake to stall indefinitely and holding connections open. By opening many such stalled connections in parallel, an attacker can exhaust file descriptors and goroutines, degrading availability of all services on the affected entrypoint. This issue has been patched in versions 2.11.38 and 3.6.9.
Metrics
Affected Vendors & Products
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Advisories
| Source | ID | Title |
|---|---|---|
 Github GHSA |
GHSA-xw98-5q62-jx94 | Traefik: tcp router clears read deadlines before tls forwarding, enabling stalled handshakes (Slowloris DOS) |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 05 Mar 2026 18:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing TLS handshake on TCP routers. When Traefik processes a TLS connection on a TCP router, the read deadline used to bound protocol sniffing is cleared before the TLS handshake is completed. When a TLS handshake read error occurs, the code attempts a second handshake with different connection parameters, silently ignoring the initial error. A remote unauthenticated client can exploit this by sending an incomplete TLS record and stopping further data transmission, causing the TLS handshake to stall indefinitely and holding connections open. By opening many such stalled connections in parallel, an attacker can exhaust file descriptors and goroutines, degrading availability of all services on the affected entrypoint. This issue has been patched in versions 2.11.38 and 3.6.9. | |
| Title | Traefik: tcp router clears read deadlines before tls forwarding, enabling stalled handshakes (slowloris doS) | |
| Weaknesses | CWE-400 | |
| References |
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| Metrics |
cvssV3_1
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Projects
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-03-05T16:15:36.437Z
Reserved: 2026-02-17T01:41:24.607Z
Link: CVE-2026-26999
Vulnrichment
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NVD
Status : Undergoing Analysis
Published: 2026-03-05T19:16:05.323
Modified: 2026-03-05T19:38:33.877
Link: CVE-2026-26999
Redhat
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OpenCVE Enrichment
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Weaknesses