CVE-2026-54761
Traefik: Kubernetes Gateway crossProviderNamespaces bypass allows HTTPRoute outside the allowlist to expose internal Traefik services
Description
Traefik is an HTTP reverse proxy and load balancer. Prior to 3.6.21 and 3.7.5, there is a high severity vulnerability in Traefik's Kubernetes Gateway provider affecting the crossProviderNamespaces allowlist. For HTTPRoute rules that declare multiple (WRR) backendRefs, Traefik evaluates the allowlist against the target backendRef.namespace instead of the route's own namespace. As a result, an HTTPRoute created in a namespace that is not allow-listed can reference a cross-provider TraefikService such as api@internal, dashboard@internal or rest@internal by pointing backendRef.namespace at an allow-listed namespace covered by a Gateway API ReferenceGrant, exposing internal Traefik services on the data plane. Exploitation requires the ability to create an accepted HTTPRoute and a matching ReferenceGrant from an allow-listed namespace; it does not require any change to Traefik static configuration, RBAC, or the deployment itself. This vulnerability is fixed in 3.6.21 and 3.7.5.
INFO
Published Date :
June 23, 2026, 8:16 p.m.
Last Modified :
June 26, 2026, 4:37 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Traefik to version 3.6.21 or later.
- Update Traefik to version 3.7.5 or later.
Public PoC/Exploit Available at Github
CVE-2026-54761 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54761.
| URL | Resource |
|---|---|
| https://github.com/traefik/traefik/releases/tag/v3.6.21 | Release Notes Patch |
| https://github.com/traefik/traefik/releases/tag/v3.7.5 | Release Notes Patch |
| https://github.com/traefik/traefik/security/advisories/GHSA-3g6v-2r68-prfc | Exploit Mitigation Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54761 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54761
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.
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Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54761 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54761 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* versions from (including) 3.7.0 up to (excluding) 3.7.5 *cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* versions up to (excluding) 3.6.21 Added Reference Type GitHub, Inc.: https://github.com/traefik/traefik/releases/tag/v3.6.21 Types: Patch, Release Notes Added Reference Type GitHub, Inc.: https://github.com/traefik/traefik/releases/tag/v3.7.5 Types: Patch, Release Notes Added Reference Type GitHub, Inc.: https://github.com/traefik/traefik/security/advisories/GHSA-3g6v-2r68-prfc Types: Exploit, Mitigation, Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 25, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-54761', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-25T12:45:14.367141Z'} -
New CVE Received by [email protected]
Jun. 23, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'traefik', 'product': 'traefik', 'versions': [{'status': 'affected', 'version': '< 3.6.21'}, {'status': 'affected', 'version': '>= 3.7.0-ea.1, < 3.7.5'}]}] Added Description Traefik is an HTTP reverse proxy and load balancer. Prior to 3.6.21 and 3.7.5, there is a high severity vulnerability in Traefik's Kubernetes Gateway provider affecting the crossProviderNamespaces allowlist. For HTTPRoute rules that declare multiple (WRR) backendRefs, Traefik evaluates the allowlist against the target backendRef.namespace instead of the route's own namespace. As a result, an HTTPRoute created in a namespace that is not allow-listed can reference a cross-provider TraefikService such as api@internal, dashboard@internal or rest@internal by pointing backendRef.namespace at an allow-listed namespace covered by a Gateway API ReferenceGrant, exposing internal Traefik services on the data plane. Exploitation requires the ability to create an accepted HTTPRoute and a matching ReferenceGrant from an allow-listed namespace; it does not require any change to Traefik static configuration, RBAC, or the deployment itself. This vulnerability is fixed in 3.6.21 and 3.7.5. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/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 Added CWE CWE-284 Added CWE CWE-863 Added Reference https://github.com/traefik/traefik/releases/tag/v3.6.21 Added Reference https://github.com/traefik/traefik/releases/tag/v3.7.5 Added Reference https://github.com/traefik/traefik/security/advisories/GHSA-3g6v-2r68-prfc