CVE-2026-33433 | Traefik up to 2.11.41/3.6.10 authentication spoofing

VDB-353928 · CVE-2026-33433 · GCVE-0-2026-33433 TRAEFIK UP TO 2.11.41/3.6.10 AUTHENTICATION SPOOFING HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 3.9 $0-$5k 1.09+ Summaryinfo A vulnerability categorized as critical has been discovered in Traefik up to 2.11.41/3.6.10. This vulnerability affects unknown code. The manipulation results in authentication spoofing. This vulnerability was named CVE-2026-33433. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component. Detailsinfo A vulnerability, which was classified as problematic, was found in Traefik up to 2.11.41/3.6.10. Affected is an unknown functionality. The manipulation with an unknown input leads to a authentication spoofing vulnerability. CWE is classifying the issue as CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes: Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.42, 3.6.11, and 3.7.0-ea.3, when `headerField` is configured with a non-canonical HTTP header name (e.g., `x-auth-user` instead of `X-Auth-User`), an authenticated attacker can inject their own canonical version of that header to impersonate any identity to the backend. The backend receives two header entries — the attacker-injected canonical one is read first, overriding Traefik's non-canonical write. Versions 2.11.42, 3.6.11, and 3.7.0-ea.3 patch the issue. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-33433 since 03/19/2026. The exploitability is told to be difficult. It is possible to launch the attack remotely. Additional levels of successful authentication are necessary for exploitation. There are neither technical details nor an exploit publicly available. Upgrading to version 2.11.42, 3.6.11 or 3.7.0-ea.3 eliminates this vulnerability. Productinfo Name Traefik Version 2.11.0 2.11.1 2.11.2 2.11.3 2.11.4 2.11.5 2.11.6 2.11.7 2.11.8 2.11.9 2.11.10 2.11.11 2.11.12 2.11.13 2.11.14 2.11.15 2.11.16 2.11.17 2.11.18 2.11.19 2.11.20 2.11.21 2.11.22 2.11.23 2.11.24 2.11.25 2.11.26 2.11.27 2.11.28 2.11.29 2.11.30 2.11.31 2.11.32 2.11.33 2.11.34 2.11.35 2.11.36 2.11.37 2.11.38 2.11.39 2.11.40 2.11.41 3.6.0 3.6.1 3.6.2 3.6.3 3.6.4 3.6.5 3.6.6 3.6.7 3.6.8 3.6.9 3.6.10 Website Product: https://github.com/traefik/traefik/ CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA CVSS-B Score: 🔒 CNA CVSS-BT Score: 🔒 CNA Vector: 🔒 CVSSv3info VulDB Meta Base Score: 4.1 VulDB Meta Temp Score: 3.9 VulDB Base Score: 4.1 VulDB Temp Score: 3.9 VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Authentication spoofing CWE: CWE-290 / CWE-287 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: Traefik 2.11.42/3.6.11/3.7.0-ea.3 Timelineinfo 03/19/2026 CVE reserved 03/27/2026 +8 days Advisory disclosed 03/27/2026 +0 days VulDB entry created 03/27/2026 +0 days VulDB entry last update Sourcesinfo Product: github.com Advisory: github.com Status: Confirmed CVE: CVE-2026-33433 (🔒) GCVE (CVE): GCVE-0-2026-33433 GCVE (VulDB): GCVE-100-353928 Entryinfo Created: 03/27/2026 15:49 Changes: 03/27/2026 15:49 (65) Complete: 🔍 Cache ID: 99:66A:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸