CVE-2026-32695

Traefik has Knative Ingress Rule Injection that Allows Host Restriction Bypass

Published Mar 27, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed

Description

Traefik is an HTTP reverse proxy and load balancer. Prior to versions 3.6.11 and 3.7.0-ea.2, Traefik's Knative provider builds router rules by interpolating user-controlled values into backtick-delimited rule expressions without escaping. In live cluster validation, Knative `rules[].hosts[]` was exploitable for host restriction bypass (for example `tenant.example.com`) || Host(`attacker.com`), producing a router that serves attacker-controlled hosts. Knative `headers[].exact` also allows rule-syntax injection and proves unsafe rule construction. In multi-tenant clusters, this can route unauthorized traffic to victim services and lead to cross-tenant traffic exposure. Versions 3.6.11 and 3.7.0-ea.2 patch the issue.

Analysis

Technical impact

Traefik’s Knative provider interpolates user‑controlled values into backtick‑delimited rule expressions without escaping, allowing syntax injection in the hosts field. An attacker can supply an entry such as tenant.example.com || Host(`attacker.com`), resulting in a router that serves attacker‑controlled hosts. This bypasses host restriction and permits unauthorized traffic to reach victim services, exposing sensitive data across tenants.

Affected Systems

Traefik v3.6.x earlier than 3.6.11 and v3.7.0-ea.1 or earlier are affected. The vulnerability exists in the Knative provider component of Traefik.

Risk and Exploitability

The CVSS score of 6.3 classifies the issue as medium severity. An EPSS score below 1% indicates a low likelihood of exploitation in the wild, and the vulnerability is not listed in CISA’s Known Exploited Vulnerabilities catalog. The attack vector is inferred as remote, via HTTP traffic configured through the Knative provider; exploitation requires an attacker to supply a malicious hosts entry in a Knative rule set.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

traefik

affected

Version	Status	Constraints
`< 3.6.11`	affected	—
`>= 3.7.0-ea.1, < 3.7.0-ea.2`	affected	—

Configuration 1 [-]

OR	cpe:2.3:a:traefik:traefik::::::::
	cpe:2.3:a:traefik:traefik:3.7.0:ea1::::::

No data.

Vendor Product Versions

Traefik

Version	Status	Scheme	Platform
`[0,3.6.11)`	affected	semver	—
`[3.7.0-ea.1,3.7.0-ea.2)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Traefik to version 3.6.11 or later, or version 3.7.0-ea.2 or later

Generated by OpenCVE AI on April 3, 2026 at 20:26 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-67jx-r9pv-98rj	Traefik has Knative Ingress Rule Injection that Allows Host Restriction Bypass

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements 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 None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Changed

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.482% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://access.redhat.com/errata/RHSA-2026:10175
https://access.redhat.com/security/cve/CVE-2026-32695
https://bugzilla.redhat.com/show_bug.cgi?id=2452235
https://github.com/traefik/traefik/releases/tag/v3.6.11
https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.2
https://github.com/traefik/traefik/security/advisories/GHSA-67jx-r9pv-98rj
https://nvd.nist.gov/vuln/detail/CVE-2026-32695
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32695.json
https://www.cve.org/CVERecord?id=CVE-2026-32695

History

Apr 3, 2026 5:45 PM Affected versions updated View changes

Type	Values Removed	Values Added
CPEs		cpe:2.3:a:traefik:traefik:::::::: cpe:2.3:a:traefik:traefik:3.7.0:ea1::::::

Mar 30, 2026 12:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Mar 30, 2026 7:15 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Traefik Traefik traefik
Vendors & Products		Traefik Traefik traefik

Mar 28, 2026 12:15 PM Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-917
References		https://nvd.nist.gov/vuln/detail/CVE-2026-32695 https://www.cve.org/CVERecord?id=CVE-2026-32695
Metrics	threat_severity `None`	cvssV3_1 `{'score': 7.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N'}` threat_severity `Important`

Mar 27, 2026 2:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Traefik is an HTTP reverse proxy and load balancer. Prior to versions 3.6.11 and 3.7.0-ea.2, Traefik's Knative provider builds router rules by interpolating user-controlled values into backtick-delimited rule expressions without escaping. In live cluster validation, Knative `rules[].hosts[]` was exploitable for host restriction bypass (for example `tenant.example.com`) \|\| Host(`attacker.com`), producing a router that serves attacker-controlled hosts. Knative `headers[].exact` also allows rule-syntax injection and proves unsafe rule construction. In multi-tenant clusters, this can route unauthorized traffic to victim services and lead to cross-tenant traffic exposure. Versions 3.6.11 and 3.7.0-ea.2 patch the issue.
Title		Traefik has Knative Ingress Rule Injection that Allows Host Restriction Bypass
Weaknesses		CWE-74
References		https://github.com/traefik/traefik/releases/tag/v3.6.11 https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.2 https://github.com/traefik/traefik/security/advisories/GHSA-67jx-r9pv-98rj
Metrics		cvssV4_0 `{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N'}`

Subscriptions

Traefik Traefik

Weaknesses

CWE-74
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-917
Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')