CVE-2026-88009

What it is

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.57, and 3.7.13, Traefik accepts a rootless HTTP/1 request target that Go stores in URL.Opaque while leaving URL.Path empty. The rewriteRequestBuilder path evaluates routing, path sanitization, forwardAuth, encodedCharacters, and access logging against a path normalized to / but forwards URL.Opaque verbatim to the backend, allowing cross-vhost routing bypass, path-scoped authorization bypass, and access-log evasion when the backend interprets the opaque target as a path. This issue is fixed in 2.11.57 and 3.7.13.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-09 19:19 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-09-10 16:18 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-09-14 19:59 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 8.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-09-10 16:18 UTC

Last modified

2026-09-14 19:59 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-444

Record status

Analyzed

Affected

• Traefik < 2.11.57
• Traefik < 3.7.13

Attack profile CVSS 4.0 · 8.8

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

High

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-88009.md and follow it. Check whether this project is affected by CVE-2026-88009. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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