Cyber Resilience

CVE-2026-54763

Auth Bypass in Traefik ≤ 2.11.51

Published
06 July 2026
Modified
08 July 2026
Patch / advisory
CVSS Score v4 7.8
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0021 11th percentile
Risk Priority 42 floored blend · peak EPSS

Summary

CVE-2026-54763 is a high-severity Improper Handling of Case Sensitivity (CWE-178) vulnerability in Traefik Traefik. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Mark-of-the-Web Bypass (T1553.005); ranked at the 11th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to IA-2 (Identification and Authentication (Organizational Users)) and IA-3 (Device Identification and Authentication) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which…

more

many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1553.005 Mark-of-the-Web Bypass Defense Impairment
Adversaries may abuse specific file formats to subvert Mark-of-the-Web (MOTW) controls.
T1195 Supply Chain Compromise Initial Access
Adversaries may manipulate products or product delivery mechanisms prior to receipt by a final consumer for the purpose of data or system compromise.
T1195.001 Compromise Software Dependencies and Development Tools Initial Access
Adversaries may manipulate software dependencies and development tools prior to receipt by a final consumer for the purpose of data or system compromise.
T1195.002 Compromise Software Supply Chain Initial Access
Adversaries may manipulate application software prior to receipt by a final consumer for the purpose of data or system compromise.
T1542.002 Component Firmware Stealth
Adversaries may modify component firmware to persist on systems.
T1553 Subvert Trust Controls Defense Impairment
Adversaries may undermine security controls that will either warn users of untrusted activity or prevent execution of untrusted programs.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-45410Same product: Traefik Traefik
CVE-2026-54764Same product: Traefik Traefik
CVE-2026-35051Same product: Traefik Traefik
CVE-2026-33433Same product: Traefik Traefik
CVE-2026-39858Same product: Traefik Traefik
CVE-2026-29054Same product: Traefik Traefik
CVE-2026-53622Same product: Traefik Traefik
CVE-2026-48020Same product: Traefik Traefik
CVE-2025-66491Same product: Traefik Traefik
CVE-2026-48491Same product: Traefik Traefik

Affected Assets

traefik
traefik
≤ 2.11.51 · 3.0.0 — 3.6.22 · 3.7.0 — 3.7.6

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 11 hardening rules · 5 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.3
  • V10.4.16
  • V10.5.1
  • V11.4.3

Mitigating Controls (NIST 800-53 r5) AI

Proper unique identification and authentication of users directly stops spoofing-based bypass of authentication.

Device identification and authentication before connection prevents spoofing of devices to bypass auth.

Authentication of non-organizational users blocks external spoofing attempts against the scheme.

Explicit requirement to protect session authenticity structurally prevents the weakness for communications.

Authenticator management ensures credentials cannot be easily spoofed or reused to bypass authentication.

Integrity verification tools detect (but do not stop) the acceptance of data lacking authenticity.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-04 full match
prevents

Protecting, conveying, and verifying identity assertions specifically prevents the spoofing that enables authentication bypass.

PR.AA-03 mostly match
prevents

Requiring authentication of users/services/hardware directly counters spoofing-based bypass when strong methods are used.

RC.RP-05 mostly match
degrades

CWE-345 directly impairs RC.RP-05's verification of restored-asset integrity/authenticity, largely defeating the outcome while still leaving other restoration-confirmation steps partially viable.

PR.AA-02 partial match
prevents

Proofing and binding identities reduces spoofing opportunities during enrollment but does not address runtime authentication implementation flaws.

PR.PS-06 partial match
prevents

Secure SDLC practices can catch and prevent case-sensitivity flaws during code review or testing, but fixing one CWE achieves negligible coverage of the broad control.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

degrades

Secure authentication control directly mitigates authentication bypass by spoofing.

degrades

Authentication information management directly addresses credential handling that prevents spoofing.

finds

Security testing can detect spoofing vulnerabilities but does not prevent them by itself.

prevents

Access control policy reduces spoofing opportunities but does not prescribe authentication mechanisms.

prevents

Identity management supports unique identities but does not guarantee resistance to spoofing.

prevents

Access rights assignment limits exposure but does not enforce authentication strength.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-345
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-290
Oracle Linux 9 (1 rule)
  • V-271525 OL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-345
RHEL 7 (3 rules)
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-290
  • V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
  • V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
RHEL 8 (3 rules)
  • V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
  • V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-290
RHEL 9 (1 rule)
  • V-257822 RHEL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-345

References