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CVE-2026-88007: Traefik is an open source HTTP reverse proxy and load balancer

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CRITICAL 9.1REMOTEUPGRADE

CVE-2026-88007 is a critical-severity flaw (CVSS 9.1) affecting traefik. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.0 until 2.11.57 and 3.7.13, the HTTP/3 entrypoint ConnContext does not call service.AddTransportOnContext, so kerberosRoundTripper uses a shared backend transport instead of a transport dedicated to each frontend connection. With HTTP/3 enabled, a backend using connection-bound NTLM or Negotiate authentication, and backend keep-alive, an unrelated client can reuse a backend

Why this priority

  • Critical severity
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score9.1 (Critical)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.6% (top 52%)
CISA exploited listNo
WeaknessCWE-287, CWE-863
Published2026-09-10
Last modified2026-09-14
Publisher (CNA): GitHub, Inc. · Vendor: traefik

Share: LinkedIn · X · Reddit

Last updated 2026-09-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

traefik traefik UPGRADE
Affected: >= 2.8.2 and < 2.11.56 · >= 3.0.0 and < 3.7.12
Fixed in: 2.11.56, 3.7.12
Safe to downgrade to: a release before 2.8.2
1. Check installed version
apt-cache policy traefik || rpm -q traefik || traefik --version
2. UPGRADE to 2.11.56 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade traefik
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade traefik
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 2.8.2 (Debian / Ubuntu)
apt-cache madison traefik sudo apt install traefik=<VERSION_BEFORE_2.8.2> sudo apt-mark hold traefik
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list traefik sudo dnf downgrade traefik-<VERSION_BEFORE_2.8.2> sudo dnf versionlock add traefik
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-88007?

traefik: upgrade to 2.11.56, 3.7.12. Exact commands for each OS are on this page.

Is CVE-2026-88007 being exploited?

CVE-2026-88007 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-88007 affect?

CVE-2026-88007 affects traefik. Severity is critical (CVSS 9.1). Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.0 until 2.11.57 and 3.7.13, the HTTP/3 entrypoint ConnContext does not call service.AddTransportOnContext, so kerberosRoundTripper uses a shared backend transport ins

How urgent is CVE-2026-88007?

Priority 49/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

Traefik vulnerabilities

Related CVEs

References

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