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CVE-2026-88010— Traefik: BasicAuth singleflight coalescing reintroduces an unauthenticated username-enumeration timing oracle

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 是一个开源的 HTTP 反向代理和负载均衡器。在 3.6.11 至 3.7.13 版本中， 中的 函数使用提交的密码和存储的秘密值来构造 BasicAuth 的 singleflight 键。因此，针对不存在的用户名的并发请求会合并到同一个键上，而针对已配置用户名的请求则执行独立的密码哈希操作，从而产生一种未经身份验证即可利用的时序差异，泄露该用户名是否存在。对于顺序执行的检查，其计算成本保持均衡；Traefik v2 以及 Digest 认证方式不受此问题影响；并且该漏洞不会泄露凭证或绕过身份验证

CVSS 6.3 · Medium EPSS 0.31% · P24

Possible ATT&CK Techniques 1 AI

T1592 · Gather Victim Host Information

Affected Version Matrix 1

VendorProduct Version RangeStatus
traefik traefik >= 3.6.11, < 3.7.13 affected
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I. Basic Information for CVE-2026-88010

Vulnerability Information
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Vulnerability Title
Traefik: BasicAuth singleflight coalescing reintroduces an unauthenticated username-enumeration timing oracle
Source: CVE Program / CVE List V5
Vulnerability Description
Traefik is an open source HTTP reverse proxy and load balancer. From 3.6.11 until 3.7.13, checkPassword in pkg/middlewares/auth/basic_auth.go constructs the BasicAuth singleflight key from the submitted password and stored secret. Concurrent requests for absent usernames therefore coalesce on one key while configured usernames perform separate password hashes, creating an unauthenticated timing discrepancy that reveals whether a username exists. Sequential checks remain cost-equalized, Traefik v2 and Digest authentication are not affected, and the issue does not disclose credentials or bypass authentication. This issue is fixed in version 3.7.13.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/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

Affected Products

Vendor Product Affected Versions CPE Subscribe
traefik traefik >= 3.6.11, < 3.7.13 -

II. Public POCs for CVE-2026-88010

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III. Intelligence Information for CVE-2026-88010

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Patches & Fixes for CVE-2026-88010 (2)

Vendor Pages for CVE-2026-88010 (1)

Other References for CVE-2026-88010 (1)

IV. Related Vulnerabilities

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