CVE-2026-35051: Traefik: ForwardAuth trustForwardHeader=false allows spoofed X-Forwarded-Prefix to bypass auth
Vulnerability summary
CVE-2026-35051 is a critical (CVSS 10.0) vulnerability in traefik. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.9% of scored vulnerabilities. 1 public exploit is recorded.
Public exploit (GitHub, Date unknown)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3 · Related 3Timeline
- 30-04-2026PublishedVulnerability first disclosed.
- 15-07-2026Last modifiedVulnerability information updated.
Description
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is an authentication bypass vulnerability in Traefik's ForwardAuth middleware when trustForwardHeader=false is configured and Traefik is deployed behind a trusted upstream proxy. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
CVSS metrics
7 scores · 4 sources · 2 versions- OSV · GoEcosystem advisory · calculated7.8HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
- OSV · ChainguardEcosystem advisory · calculated7.8HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
- NVDNIST7.8HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/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
- CVE.orgCNA8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:NDiffers
- OSV · GoEcosystem advisory · calculated10.0CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
EPSS trend
Probability
0.27%
Chance of exploitation in the next 30 days
Percentile
19%
Versus all other CVEs
30-day change
Decrease -0.04 pp
From 0.31% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundTraefik
Maturity: poc
Weaknesses
CWE · root cause- CWE-345Insufficient Verification of Data AuthenticityThe product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
- CWE-501Trust Boundary ViolationThe product mixes trusted and untrusted data in the same data structure or structured message.
Affected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard2 products
- traefik-3.5All versions (No fix recorded)
- traefik-fips-3.5All versions (No fix recorded)
Github.com/traefik/traefik2 products
- v2< 2.11.43
- v3≥ 3.0.0-beta1, < 3.6.14 | ≥ 3.7.0-ea.1, < 3.7.0-rc.2
Github.com/traefik1 product
- traefik≤ 1.7.34 | All versions (No fix recorded)
Traefik1 product
- traefik≥ 3.0.0-beta1, < 3.6.14 | ≥ 3.7.0-ea.1, < 3.7.0-rc.2 | < 2.11.43 | ≥ 3.0.0, < 3.6.14 | 3.7.0:ea1 | 3.7.0:ea2 | 3.7.0:ea3 | 3.7.0:rc1
4 vendors · 6 products
References
11 links- github.com/traefik/traefik/security/advisories/GHSA-6384-m2mw-rf54X Refsource CONFIRMWEBAdvisoryExploitPatchVendor Advisory
- github.com/traefik/traefikPACKAGE