CVE-2026-125371 PUBLISHED

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

Assigner: VulnCheck
Reserved: 09.11.2026 Published: 09.11.2026 Updated: 09.11.2026

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.

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS Score: 6.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	High	Integrity	Low	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS Score: 4.8

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	Low
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	tinyproxy
Product	tinyproxy
Versions	Default: unaffected affected from 0 to 1.11.3 (incl.) Version 3991ac8f98c6a9f05b3265018b812dbf2ca92c28 is unaffected

CVE-2026-125371 PUBLISHED

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

Metrics

Product Status

Credits

References

Problem Types