Upstream information
Description
Traefik is an open source HTTP reverse proxy and load balancer. From 3.2.0 until 3.7.13, Traefik entrypoint defenses aliasHeadersStrategy, underscoreHeadersStrategy, and forwardedHeaders inspect req.Header but not req.Trailer, allowing an unauthenticated client to submit an aliasing or trusted header name in an HTTP/1.1 chunked trailer or an HTTP/2 trailer. When the retry or buffering middleware reads the body before the reverse proxy clones the request, the attacker-controlled trailer value reaches a backend that merges trailers into the header namespace, bypassing the documented delete or reject behavior and potentially spoofing identity or forwarded routing data. This issue is fixed in 3.7.13.SUSE information
Overall state of this security issue: Resolved
This issue is currently rated as having important severity.
| CVSS detail | National Vulnerability Database |
|---|---|
| Base Score | 7.4 |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| Attack Vector | Network |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | High |
| Integrity Impact | High |
| Availability Impact | None |
| CVSSv3 Version | 3.1 |
| CVSS detail | CNA (GitHub) |
|---|---|
| Base Score | 7 |
| Vector | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| Attack Vector | Network |
| Attack Complexity | High |
| Attack Requirements | None |
| Privileges Required | None |
| User Interaction | None |
| Vulnerable System Confidentiality Impact | None |
| Vulnerable System Integrity Impact | None |
| Vulnerable System Availability Impact | None |
| Subsequent System Confidentiality Impact | High |
| Subsequent System Integrity Impact | High |
| Subsequent System Availability Impact | None |
| CVSSv4 Version | 4.0 |
SUSE Security Advisories:
- SUSE-SU-2026:23855-1, published 2026-09-21T12:26:05Z
- SUSE-SU-2026:23863-1, published 2026-09-21T12:36:27Z
List of released packages
| Product(s) | Fixed package version(s) | References |
|---|
SUSE Timeline for this CVE
CVE page created: Mon Sep 21 16:54:48 2026CVE page last modified: Fri Sep 25 12:55:34 2026