Tinyproxy through 1.11.3 contains an access control bypass vulnerability in acl_string_processing() in src/acl.c that
Source GCVE Database
Not known to be exploited · CVSS 6.3 Medium.
Data as of 10 Nov 2026, 01:33 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 6.3 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 4.8 |
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| tinyproxytinyproxy | Affected
| Fixed in– |
GitHubtinyproxy/tinyproxypkg:github/tinyproxy/tinyproxyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, administrators should consider restricting access to trusted IPs by other means or disabling the vulnerable ACL functionality if possible.
Description
Tinyproxy versions through 1.11.3 have an access control bypass vulnerability in the acl_string_processing() function. The flaw arises because the function compares only trailing hostname characters without validating DNS label boundaries. This allows an attacker who controls the PTR record for their IP address to bypass deny-by-default access control lists (ACLs) by matching allowed hostnames improperly.
References
- nvd.nist.gov/vuln/detail/CVE-2026-125371 (opens in a new tab)
- github.com/tinyproxy/tinyproxy/issues/627 (opens in a new tab)
- github.com/tinyproxy/tinyproxy/commit/3991ac8f98c6a9f05b3265018b812dbf2ca92c28 (opens in a new tab)
- github.com/tinyproxy/tinyproxy (opens in a new tab)
- github.com/tinyproxy/tinyproxy/blob/1.11.3/src/acl.c (opens in a new tab)
- vulncheck.com/advisories/tinyproxy-through-1.11.3-hostname-acl-allow-list-bypass-via-suffix-match (opens in a new tab)