Improper Neutralization of CRLF Sequences in HTTP Headers in Apache Tomcat

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

• CVE-2014-0099: 8.84% estimated exploitation activity in the next 30 days; percentile 95.20 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Integer overflow in java/org/apache/tomcat/util/buf/Ascii.java in Apache Tomcat before 6.0.40, 7.x before 7.0.53, and 8.x before 8.0.4, when operated behind a reverse proxy, allows remote attackers to conduct HTTP request smuggling attacks via a crafted Content-Length HTTP header.

Published by the source

14 May 2022, 01:10 UTC

Last modified by the source

14 Apr 2025, 21:42 UTC

Source last checked

26 Oct 2026, 16:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-xh5x-j8jf-pcpx

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# Patch Next advisory brief: CVE-2014-0099

Advisory: Improper Neutralization of CRLF Sequences in HTTP Headers in Apache Tomcat
IDs: CVE-2014-0099, GHSA-xh5x-j8jf-pcpx
Record: https://patchnext.com/advisories/cve-2014-0099 (revision 1, source checked 26 Oct 2026, 16:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.apache.tomcat:tomcat-util 8.0.6, 7.0.54, 6.0.40; org.apache.tomcat:tomcat 8.0.6, 7.0.54, 6.0.40. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.tomcat:tomcat-util: affected < 6.0.40; >= 7.0.0, < 7.0.54; >= 8.0.0, < 8.0.6; fixed in 8.0.6, 6.0.40, 7.0.54
- Maven org.apache.tomcat:tomcat: affected < 6.0.40; >= 7.0.0, < 7.0.54; >= 8.0.0, < 8.0.6; fixed in 8.0.6, 6.0.40, 7.0.54

## Suggested inspection (read-only)
- Maven org.apache.tomcat:tomcat-util: check the installed version with your package manager.
- Maven org.apache.tomcat:tomcat: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apache.tomcat:tomcat-util, org.apache.tomcat:tomcat.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-xh5x-j8jf-pcpx (GitHub-reviewed advisory GHSA-xh5x-j8jf-pcpx lists affected ranges: Maven org.apache.tomcat:tomcat >=0 =7.0.0 =8.0.0 =0 =7.0.0 =8.0.0 <8.0.6)

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