Tinyproxy up to 1.11.3 Header Host authentication spoofing

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability has been found in Tinyproxy up to 1.11.3 and classified as critical. Affected by this issue is some unknown functionality of the component Header Handler. This manipulation of the argument Host causes authentication spoofing. The identification of this vulnerability is CVE-2026-55202. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in Tinyproxy up to 1.11.3 and classified as critical. Affected by this vulnerability is an unknown part of the component Header Handler. The manipulation of the argument Host with an unknown input leads to a authentication spoofing vulnerability. The CWE definition for the vulnerability is CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Tinyproxy through 1.11.3, fixed in commit 09312a1, fails to properly validate the Host header during stathost detection, allowing unauthenticated attackers to access the stats page by injecting a matching Host header or bypass detection via port manipulation. Remote attackers can trigger unauthorized access to internal proxy statistics or misroute requests as transparent proxy connections to circumvent access controls.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-55202 since 06/16/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 321703 (Linux Distros Unpatched Vulnerability : CVE-2026-55202), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability. Applying the patch 09312a185ae25cc486b4ff5987638a7917a48bce is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (321703), EUVD (EUVD-2026-37786) and CERT Bund (WID-SEC-2026-1999). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Fedora Linux
  • Open Source Tinyproxy

Productinfo

Type

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.2
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authentication spoofing
CWE: CWE-290 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 321703
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-55202

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Patch: 09312a185ae25cc486b4ff5987638a7917a48bce

Timelineinfo

06/16/2026 CVE reserved
06/17/2026 +1 days Advisory disclosed
06/17/2026 +0 days VulDB entry created
06/21/2026 +3 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-55202 (🔒)
GCVE (CVE): GCVE-0-2026-55202
GCVE (VulDB): GCVE-100-372109
EUVD: 🔒
CERT Bund: WID-SEC-2026-1999 - Tinyproxy: Mehrere Schwachstellen

Entryinfo

Created: 06/17/2026 21:56
Updated: 06/21/2026 01:50
Changes: 06/17/2026 21:56 (77), 06/18/2026 00:00 (1), 06/18/2026 13:03 (7), 06/19/2026 09:45 (1), 06/21/2026 01:50 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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