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Mallory
HighPublic exploit

Squid Proxy HTTP Authentication Credentials Disclosure

IdentifiersCVE-2025-62168CWE-209· Generation of Error Message…

CVE-2025-62168 is an information disclosure vulnerability in Squid, the web caching proxy, affecting versions prior to 7.2. During error handling, Squid fails to properly redact sensitive HTTP authentication material before embedding request debugging details into generated error content, including administrator mailto links controlled by the email_err_data feature. As a result, error pages may expose the HTTP Authorization header and associated credentials such as usernames, passwords, bearer tokens, or other security tokens. The issue affects both forward and reverse proxy deployments and can occur even when Squid itself is not configured to perform HTTP authentication, because proxied requests may still carry authentication data destined for upstream or backend services.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

A remote attacker can trigger a Squid error response and recover authentication credentials disclosed in the resulting error page content. This can expose user credentials, bearer tokens, or internal application security tokens used by trusted clients or backend-integrated applications. In reverse proxy or load-balancing scenarios, the flaw may reveal credentials used internally by web applications, enabling unauthorized access to protected resources, session or token theft, and follow-on compromise of upstream services. The issue is an information disclosure vulnerability rather than direct code execution or denial of service.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, disable inclusion of debugging data in administrator mailto links by setting "email_err_data off" in squid.conf. Additionally, reduce exposure by limiting untrusted clients' ability to trigger proxy error pages, avoiding transmission of sensitive Authorization material through vulnerable proxy paths where possible, and reviewing error-page behavior in both forward and reverse proxy deployments.

Remediation

Patch, then assume compromise.

Upgrade Squid to version 7.2 or later, where sensitive headers are redacted during error handling. The referenced fix is included in Squid 7.2 and associated with advisory GHSA-c8cc-phh7-xmxr. If maintaining downstream packages, ensure the vendor backport includes the header-redaction fix corresponding to the upstream patch.
PUBLIC EXPLOITS

Exploits

1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.

VALID 1 / 1 TOTALView more in app
CVE-2025-62168MaturityPoCVerified exploit

This repository provides a Proof-of-Concept (PoC) exploit for CVE-2025-62168, an information disclosure vulnerability in Squid Proxy (versions < 7.2). The vulnerability allows an attacker to inject a custom HTTP header containing a sensitive token (such as a JWT) into a proxied request. When Squid generates an error page (e.g., by requesting a non-existent domain), it may reflect the injected header value inside the mailto diagnostic block of the error page, exposing the token to the attacker. The main exploit script, 'cve-2025-62168.py', is a Python 3 async tool that: - Connects to a user-specified Squid proxy (via --proxy argument) - Sends a request with a custom header (X-Test-Leak) containing a demo JWT token - Forces Squid to generate an error page by requesting a non-existent domain - Parses the returned HTML for the mailto block - Extracts and decodes the leaked token Supporting files include 'payload.json' (JWT payload), 'token.txt' (Bash script to generate the JWT), and 'requirements.txt' (Python dependencies). The README.md provides detailed technical background, usage instructions, and mitigation advice. The exploit demonstrates a network-based attack vector and is a clear, functional PoC for the described vulnerability.

nehkarkDisclosed Nov 25, 2025pythonbashnetwork
EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
Squid-CacheSquidapplication

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Detection signatures

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Vendor-by-vendor mapping

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Social activity7

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