traefik: Insufficient Verification of Data Authenticity
CVE-2026-35051 is a critical-severity insufficient verification of data authenticity vulnerability in traefik, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected traefik versions: < 2.11.43; >= 3.0.0-beta1, < 3.6.14; >= 3.7.0-ea.1, < 3.7.0-rc.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.27% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of traefik you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Traefik | traefik | < 2.11.43; >= 3.0.0-beta1, < 3.6.14; >= 3.7.0-ea.1, < 3.7.0-rc.2 | Not stated |
| Red Hat | Red Hat OpenShift Dev Spaces 3.28 | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.8 | High | CNA (github.com) |
| CVSS 3.1 | 10.0 | Critical | NVD |
| CVSS 3.1 | 8.2 | High | CNA |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insufficient Verification of Data Authenticity
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
More Insufficient Verification of Data Authenticity vulnerabilities (CWE-345)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- github.com/traefik/traefik/releases/tag/v2.11.43Product, Release Notes
- github.com/traefik/traefik/releases/tag/v3.6.14Product, Release Notes
- github.com/traefik/traefik/releases/tag/v3.7.0-rc.2Product, Release Notes
Other references
Other vulnerabilities in traefik
- 8.7 High severity
- 8.7 High severity
- 9.3 Critical severity
- 8.7 High severity
- 8.7 High severity
- 8.7 High severity
Recent Insufficient Verification of Data Authenticity vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 9.1 Critical severity
- 8.2 High severity
- 8.2 High severity
- 7.5 High severity
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