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GO-2026-6467 CVE-2026-88004 GHSA-v67p-phpq-fc8x

Traefik entrypoint header-name sanitization bypassed via request trailers in github.com/traefik/traefik

High Go
Severity
0.0 / 10
High · CVSS 4.0
Exploit chance (EPSS)
0.45%
Chance of exploitation in the next 30 days. Higher than 39.29% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-436 Interpretation Conflict
CWE-807 Reliance on Untrusted Inputs in a Security Decision
Fix
3.7.13
Upgrade github.com/traefik/traefik/v3 to this version or later

Description

Traefik entrypoint header-name sanitization bypassed via request trailers in github.com/traefik/traefik

Affected versions

Go

PackageVulnerableFixed in
github.com/traefik/traefik
all versions
No fix yet
github.com/traefik/traefik/v2
all versions
No fix yet
github.com/traefik/traefik/v3
>= 3.2.0, < 3.7.13
3.7.13

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

github.com/traefik/traefik/v3 Go → 3.7.13

go
go get github.com/traefik/traefik/v3@v3.7.13 && go mod tidy

Severity breakdown

CVSS 4.0 0.0

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

Attack vector
Network
Attack complexity
High
Attack requirements
None
Privileges required
None
User interaction
None
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
None
Availability (vulnerable system)
None
Confidentiality (subsequent systems)
High
Integrity (subsequent systems)
High
Availability (subsequent systems)
None

CVSS 3.1 7.4

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
High
Integrity
High
Availability
None

Weakness

CWE-436: Interpretation Conflict

Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.

CWE-807: Reliance on Untrusted Inputs in a Security Decision

The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.

How to prevent it
  • Architecture and Design: Store state information and sensitive data on the server side only. Ensure that the system definitively and unambiguously keeps track of its own state and user state and has rules defined for legitimate state transitions. Do not allow any application user to affect state directly in any way other than through legitimate actions leading to state transitions. If information must be stored on the client, do not do so without encryption and integrity checking, or otherwise having a mechanism on the server side to catch tampering. Use a message authentication code (MAC) algorithm, such as Hash Message Authentication Code (HMAC) [REF-529]. Apply this against the state or sensitive data that has to be exposed, which can guarantee the integrity of the data - i.e., that the data has not been modified. Ensure that a strong hash function is used (CWE-328).
  • Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. With a stateless protocol such as HTTP, use a framework that maintains the state for you. Examples include ASP.NET View State [REF-756] and the OWASP ESAPI Session Management feature [REF-45]. Be careful of language features that provide state support, since these might be provided as a convenience to the programmer and may not be considering security.
  • Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Operation, Implementation: When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
  • Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Identify all inputs that are used for security decisions and determine if you can modify the design so that you do not have to rely on submitted inputs at all. For example, you may be able to keep critical information about the user's session on the server side instead of recording it within external data.

References

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GO-2026-6558
Traefik: BasicAuth singleflight coalescing reintroduces an unauthenticated username-enumeration timing oracle
Medium Also affects github.com/traefik/traefik
GHSA-f52w-8j3h-j724
Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
High Also affects github.com/traefik/traefik
GHSA-w4v4-9rw7-5326
Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization
Critical Also affects github.com/traefik/traefik
GHSA-qqjf-53cj-pwvv
Traefik HTTP/3 Backend NTLM Connection Reuse
Critical Also affects github.com/traefik/traefik
GHSA-rf44-j88r-hh8c
Traefik: ForwardAuth identity spoofing via dot-form header alias
High Also affects github.com/traefik/traefik
GHSA-7ghq-v6jf-g56c
Traefik: respondingTimeouts.readTimeout is not applied to HTTP/3, leaving slow-body uploads unbounded
Medium Also affects github.com/traefik/traefik
GHSA-62fc-8686-hfmq
Traefik: `allowCrossNamespace=false` bypass via `@kubernetescrd` TraefikService backendRef
Medium Also affects github.com/traefik/traefik
GO-2026-6209
Traefik: Gateway API route identity collision allows cross-namespace backend hijacking
High Also affects github.com/traefik/traefik
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