CVE-2026-125371— Tinyproxy through 1.11.3 Hostname ACL Allow-List Bypass via Suffix Match

Quick assessment

Affected

tinyproxy tinyproxy

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.

Tinyproxy 1.11.3 及以下版本在的函数中存在访问控制绕过漏洞。该函数在比较主机名时仅检查末尾字符，未验证 DNS 标签边界。若攻击者能够控制其源 IP 地址的 PTR 记录（例如），则即使默认策略为拒绝（deny-by-default），攻击者仍可绕过访问控制列表（ACL）中的条目，从而利用该代理。

CVSS 4.8 · Medium Updated Nov 10, 2026

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

Tinyproxy through 1.11.3 Hostname ACL Allow-List Bypass via Suffix Match

Source: CVE Program / CVE List V5

Vulnerability Description

Tinyproxy through 1.11.3 contains an access control bypass vulnerability in acl_string_processing() in src/acl.c that compares only trailing hostname characters without checking DNS label boundaries. Attackers controlling the PTR record for their source IP, such as untrusted.net, can satisfy an 'Allow trusted.net' entry to use the proxy despite deny-by-default ACLs.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Source: CVE Program / CVE List V5

Vulnerability Type

部分比较

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
tinyproxy	tinyproxy	0 ~ 1.11.3	-

II. Public POCs for CVE-2026-125371

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-125371

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Other References for CVE-2026-125371 (4)

https://github.com/tinyproxy/tinyproxy/blob/1.11.3/src/acl.c#L156-L174 technical-description
https://github.com/tinyproxy/tinyproxy/commit/3991ac8f98c6a9f05b3265018b812dbf2ca92c28 patch
https://github.com/tinyproxy/tinyproxy/issues/627 issue-tracking
Tinyproxy through 1.11.3 Hostname ACL Allow-List Bypass via Suffix Match | Advisories | VulnCheck third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-125371

IV. Related Vulnerabilities

Same product: tinyproxy

Same vendor: tinyproxy

Same weakness: CWE-187