CVE-2026-29054
HIGHTraefik: lowercase `Connection` tokens can delete traefik-managed forwarded identity headers (for example, `X-Real-Ip`)
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/traefik/traefik/v2🐹github.com/traefik/traefik/v3Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Traefik is an HTTP reverse proxy and load balancer. From version 2.11.9 to 2.11.37 and from version 3.1.3 to 3.6.8, there is a potential vulnerability in Traefik managing the Connection header with X-Forwarded headers. When Traefik processes HTTP/1.1 requests, the protection put in place to prevent the removal of Traefik-managed X-Forwarded headers (such as X-Real-Ip, X-Forwarded-Host, X-Forwarded-Port, etc.) via the Connection header does not handle case sensitivity correctly. The Connection tokens are compared case-sensitively against the protected header names, but the actual header deletion operates case-insensitively. As a result, a remote unauthenticated client can use lowercase Connection tokens (e.g. Connection: x-real-ip) to bypass the protection and trigger the removal of Traefik-managed forwarded identity headers. This issue has been patched in versions 2.11.38 and 3.6.9.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/traefik/traefik/v2 | ≥ 2.11.9&&< 2.11.38 | 2.11.38 |
| 🐹Go | github.com/traefik/traefik/v3 | ≥ 3.1.3&&< 3.6.9 | 3.6.9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/traefik/traefik/v2. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/traefik/traefik/v2 to 2.11.38 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-29054 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-29054 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-29054. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-29054 in your dependencies?
O3 detects CVE-2026-29054 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.