CVE-2026-88009
HIGHDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 19% of all known CVEs.
References
Related Vulnerabilities
Other CWE-444 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-22536 | Critical | 10.0 | 98% | KEV | - |
| CVE-2025-61884 | High | 7.5 | 96% | KEV + Ransom | - |
| CVE-2020-9490 | High | 7.5 | 89% | - | Fix |
| CVE-2023-41265 | Critical | 9.6 | 88% | KEV + Ransom | - |
| CVE-2023-25690 | Critical | 9.8 | 85% | - | Fix |
| CVE-2022-32214 | Medium | 6.5 | 82% | - | Fix |
Common questions
How do I fix CVE-2026-88009?
Upgrade traefik to 3.7.13 or later.
Is CVE-2026-88009 being actively exploited?
Not that we know of. CVE-2026-88009 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.27% is the estimated probability that it will be exploited in the next 30 days. That is higher than 19% of all scored CVEs.
How severe is CVE-2026-88009?
CVE-2026-88009 has a CVSS v3 base score of 8.2, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-88009 affect?
Published advisories record a fix for traefik (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-14.