Description
Traefik from v3.2.0 before v3.7.14 contains an authentication bypass vulnerability in the experimental FastProxy connection pool, which fails to pin NTLM/Negotiate-authenticated backend connections to their frontend connection. Unauthenticated clients can be handed a pooled keep-alive backend connection where a victim completed an NTLM or Negotiate handshake, letting them read victim data and act as that victim.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| traefik | traefik | 3.2.0 – < 3.7.14 | 3.7.14 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | traefik | 3.7.16-1.1 | openSUSE-SU-2026:12281-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | traefik-3.6 | No fix yet | — |
Advisories 1
- openSUSE-SU-2026:12281-1 traefik-3.7.16-1.1 on GA media SUSE / openSUSE Security Updates · Oct 27, 2026
References
- GitHub Security Advisory (GHSA-53qr-784g-cj35) vendor-advisory
- VulnCheck Advisory: Traefik v3.2.0 before v3.7.14 FastProxy NTLM/Negotiate Connection Pool Identity Leak third-party-advisory