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Improper Input ValidationWeakness · CWE-20

CVE-2025-24501

MEDIUM · 5.3 CVSS v4.0 Published 2025-01-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An improper input validation allows an unauthenticated attacker to alter PAM logs by sending a specially crafted HTTP request.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This is an improper input validation vulnerability in an authentication-related component that logs to PAM (Pluggable Authentication Modules). An unauthenticated attacker can send specially crafted HTTP requests to inject or alter PAM log entries, potentially obscuring attack痕迹 or creating false log entries for social engineering purposes.

MitigationImplement strict input validation on all HTTP request parameters before they are written to PAM logs. Consider sanitizing or rejecting special characters that could be used for log injection.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the HTTP authentication component that logs to PAM
    Review your web server or application server configuration files (e.g., httpd.conf, nginx.conf, application config) to locate modules or handlers that process HTTP authentication and forward results to PAM. Look for directives like 'PAMAuthentication' or references to pam_unix, pam_krb5, or similar PAM modules in the authentication chain.
    Affected if Your environment uses a web server or application framework that forwards HTTP authentication credentials or results to PAM for validation.
  2. Determine the installed version of the authentication component
    Run the package manager command appropriate to your system (e.g., 'rpm -q <package-name>', 'dpkg -l <package-name>', or check the binary version with '<binary> -v' or '--version') for the software that handles the HTTP-to-PAM authentication.
    Affected if The installed version matches or falls within an affected version range if such ranges become available from the vendor.
  3. Verify PAM logging from HTTP requests is enabled
    Examine the PAM configuration files in /etc/pam.d/ (or equivalent) and the application-specific configuration. Look for service entries that handle web authentication and confirm that logging modules (like pam_unix.so, pam_krb5.so with logging enabled) are configured.
    Affected if PAM modules configured for HTTP authentication have logging capabilities enabled and are actively writing to system logs (/var/log/secure, /var/log/auth.log, or similar).
  4. Inspect PAM logs for suspicious entries
    Review PAM authentication logs (typically /var/log/secure, /var/log/auth.log, or /var/log/messages) for the web service account. Search for entries containing unexpected characters (newlines, carriage returns, tab characters) or patterns that suggest log injection attempts.
    Affected if Log entries contain unusual formatting, multiple entries from single requests, or embedded control characters that were not intentionally logged.
  5. Test for log injection vulnerability
    Send a crafted HTTP request to your authentication endpoint with special characters in headers (e.g., username parameter containing '\n' or '\r\n') or parameters. Then verify if these characters appear literally in the PAM logs without sanitization.
    Affected if The special characters from the HTTP request appear unmodified in the PAM logs, indicating input is not being validated before logging.

Your environment is affected if you run a web server or application that forwards HTTP authentication to PAM and the PAM logs show unsanitized input from HTTP requests.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict input validation on all HTTP request parameters before they are written to PAM logs. Consider sanitizing or rejecting special characters that could be used for log injection.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-24501 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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