Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-41263— Traefik: BasicAuth middleware: timing side-channel vulnerability

Quick assessment

Affected
traefik traefik
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Traefik是Traefik开源的一款反向代理与负载均衡工具。 Traefik 2.11.43之前版本、3.6.14之前版本和3.7.0-rc.2之前版本存在安全漏洞，该漏洞源于BasicAuth中间件中用于常量时间比较的变量始终解析为空字符串，导致比较短路，可能允许攻击者通过响应时间差异枚举有效用户名。

AI Predicted 5.3 Difficulty: Easy EPSS 0.41% · P33

Possible ATT&CK Techniques 1 AI

T1595.001 · Scanning IP Blocks

Affected Version Matrix 3

VendorProduct Version RangeStatus
traefik traefik < 2.11.43 affected
>= 3.0.0-beta1, < 3.6.14 affected
>= 3.7.0-ea.1, < 3.7.0-rc.2 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-41263

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Traefik: BasicAuth middleware: timing side-channel vulnerability
Source: CVE Program / CVE List V5
Vulnerability Description
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a timing side-channel vulnerability in Traefik's BasicAuth middleware that allows an attacker to enumerate valid usernames through response-time differences. The variable intended to hold a constant-time fallback secret always resolves to an empty string, causing the constant-time comparison to short-circuit in microseconds rather than performing a full bcrypt evaluation. This restores the original timing oracle and makes it possible to distinguish existing users from non-existing ones by measuring authentication response times. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
通过时间差异性导致的信息暴露
Source: CVE Program / CVE List V5
Vulnerability Title
Traefik 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Traefik是Traefik开源的一款反向代理与负载均衡工具。 Traefik 2.11.43之前版本、3.6.14之前版本和3.7.0-rc.2之前版本存在安全漏洞，该漏洞源于BasicAuth中间件中用于常量时间比较的变量始终解析为空字符串，导致比较短路，可能允许攻击者通过响应时间差异枚举有效用户名。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
traefik traefik < 2.11.43 -

II. Public POCs for CVE-2026-41263

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-41263

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-41263 (1)

Vendor Pages for CVE-2026-41263 (3)

Same Patch Batch · traefik · 2026-04-30 · 5 CVEs total

CVE-2026-41174 Traefik Kubernetes CRD allows unauthorized cross-namespace middleware binding
CVE-2026-35051 Traefik: ForwardAuth trustForwardHeader=false allows spoofed X-Forwarded-Prefix to bypass
CVE-2026-39858 Traefik: Forwarded alias spoofing top pre-auth decision bypass
CVE-2026-40912 Traefik: StripPrefixRegex auth bypass via Path/RawPath desync

IV. Related Vulnerabilities

Same product: traefik
Same vendor: traefik
Same weakness: CWE-208

V. Comments for CVE-2026-41263

No comments yet

Leave a comment