Traefik is a widely deployed reverse proxy/load balancer; this auth-bypass enables cross-user backend access and impersonation across cloud/web deployments.
CVE-2026-88007
Traefik HTTP/3 auth bypass allows backend connection reuse to impersonate users
Is CVE-2026-88007 being exploited?
Not confirmed. CVE-2026-88007 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.33% probability of exploitation in the next 30 days.
How severe is CVE-2026-88007?
CVE-2026-88007 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-88007?
Yes. A fix has been recorded for CVE-2026-88007. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-88007 affect?
CVE-2026-88007 affects Traefik 2.11.0 - 2.11.56, Traefik 3.7.0 - 3.7.12, Configurations: HTTP/3 enabled + backends using NTLM/Negotiate auth with keep-alive. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-88007?
Upgrade to 2.11.57 or 3.7.13; or disable HTTP/3 and backend keep-alive until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker on HTTP/3 frontend can reuse backend NTLM/Negotiate-authenticated connections to read victim-only data and act as that user.
Immediate action required
- affected>= 2.11.0 and < 2.11.57
- affected>= 3.0.0 and < 3.7.13
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.