SEPTEMBER 14, 2026
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Case File

CVE-2026-88011

MEDIUM · CVSS 5.3 EPSS 0.25% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-10 · Last synced 2026-09-14

CyberRota Analysis

AI-Generated

Nginx is vulnerable to identity spoofing due to improper handling of client-supplied dot-form headers, which can lead to backend services consuming incorrect identity information. This issue arises when Traefik forwards these headers without proper normalization, allowing attackers to manipulate authentication data. Organizations using Traefik versions prior to 2.11.56 or between 3.0.0 and 3.7.12 should prioritize applying the available mitigations to prevent potential security breaches.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-88011
Severity
MEDIUM
CVSS
5.3
EPSS
0.25%
Nginx

Original NVD Description

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.56, and from 3.0.0 until 3.7.12, a client-supplied dot-form header such as X.Authenticated.User survives ForwardAuth replacement and underscoreHeadersStrategy because Go treats it as distinct from X-Authenticated-User while normalization-prone CGI, WSGI, PHP, and NGINX backends collapse both names. A backend can consequently consume the client value instead of the identity Traefik asserted, allowing identity spoofing for any header managed by Traefik. The aliasHeadersStrategy protection is disabled by default and must be configured as delete or reject. The mitigation is available in 2.11.56 and 3.7.12.