CVE-2026-54763

Home/CVE/Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestA

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Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestA

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 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.

EPSS 0.00272

EPSS exploitation odds0.27% · top 81%

Monitor

⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)

No Sigma yet — build one → YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-54763, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

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Severity & exploitation scoring

EPSS exploitation probability

0.27%

Top 81%odds of exploitation in the next 30 days

CVSS metric silhouette

No structured CVSS vector for this CVE. Older entries often have only a numeric base score - the metric breakdown radar requires a full AV:_/AC:_/... vector string published by NVD.

SSVC triage

No SSVC vulnrichment for this CVE. CISA's Vulnrichment program scores newer CVEs (~2024 onwards) plus selected older critical ones. Use the EPSS probability + KEV status to triage instead.

Attack path

Full kill chain

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ATT&CK techniques

Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.

T1036.001 · Invalid Code Signature T1134 · Access Token Manipulation T1134.001 · Token Impersonation/Theft T1528 · Steal Application Access Token T1539 · Steal Web Session Cookie T1550.004 · Web Session Cookie T1553.002 · Code Signing T1557 · Adversary-in-the-Middle

▤ Build a SIEM detection for these techniques

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CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-111 · JSON Hijacking (aka JavaScript Hijacking) CAPEC-CAPEC-141 · Cache Poisoning CAPEC-CAPEC-142 · DNS Cache Poisoning CAPEC-CAPEC-148 · Content Spoofing CAPEC-CAPEC-21 · Exploitation of Trusted Identifiers CAPEC-CAPEC-218 · Spoofing of UDDI/ebXML Messages CAPEC-CAPEC-22 · Exploiting Trust in Client CAPEC-CAPEC-384 · Application API Message Manipulation via Man-in-the-Middle CAPEC-CAPEC-385 · Transaction or Event Tampering via Application API Manipulation CAPEC-CAPEC-386 · Application API Navigation Remapping CAPEC-CAPEC-387 · Navigation Remapping To Propagate Malicious Content CAPEC-CAPEC-388 · Application API Button Hijacking

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Weakness Classification

CWE-178Improper Handling of Case Sensitivity
CWE-290Authentication Bypass by Spoofing
CWE-345Insufficient Verification of Data Authenticity

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Related CVEs

CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row.

CVE-1999-0239 Netscape FastTrack Web server lists files when a lowercase "get" command is used... 1 same CWE-178 HIGH CVE-2000-0497 IBM WebSphere server 3.0.2 allows a remote attacker to view source code of a JSP... same CWE-178 HIGH CVE-2000-0498 Unify eWave ServletExec allows a remote attacker to view source code of a JSP pr... same CWE-178 HIGH CVE-2000-0499 The default configuration of BEA WebLogic 3.1.8 through 4.5.1 allows a remote at... same CWE-178 HIGH CVE-1999-0012 Some web servers under Microsoft Windows allow remote attackers to bypass access... same CWE-290 HIGH CVE-2009-1048 The web interface on the snom VoIP phones snom 300, snom 320, snom 360, snom 370... same CWE-290 CRITICAL CVE-2013-5661 Cache Poisoning issue exists in DNS Response Rate Limiting. same CWE-290 MEDIUM CVE-2017-6405 An issue was discovered in Veritas NetBackup 8.0 and earlier and NetBackup Appli... same CWE-290 HIGH

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References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://github.com/traefik/traefik/commit/108a5264473a2cbc8f12d6d691a3c6553cdf2c1b

https://github.com/traefik/traefik/pull/13262

https://github.com/traefik/traefik/security/advisories/GHSA-x677-9fxg-v5c5