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HIGH

httpd: Use-after-free by limiting unregistered HTTP method (Optionsbleed)

Published Sep 18, 2017

Description

Apache httpd allows remote attackers to read secret data from process memory if the Limit directive can be set in a user's .htaccess file, or if httpd.conf has certain misconfigurations, aka Optionsbleed. This affects the Apache HTTP Server through 2.2.34 and 2.4.x through 2.4.27. The attacker sends an unauthenticated OPTIONS HTTP request when attempting to read secret data. This is a use-after-free issue and thus secret data is not always sent, and the specific data depends on many factors including configuration. Exploitation with .htaccess can be blocked with a patch to the ap_limit_section function in server/core.c.

Affected products

Remediation

Red Hat statement

This issue affects the versions of httpd as shipped with Red Hat Enterprise Linux 5, 6, and 7. This issue affects the versions of httpd24-httpd as shipped with Red Hat Software Collections. Product Security has rated this issue as having Moderate security impact. In order to be vulnerable, .htaccess files need to contain an invalid or not globally registered HTTP method in a "Limit" directive.

Red Hat mitigation

This issue can be mitigated by configuring httpd to disallow the use of the "Limit" configuration directive in .htaccess files. The set of directives that can be used in .htaccess files is configured using the "AllowOverride" directive. Refer to Red Hat Bugzilla bug 1490344 for further details: https://bugzilla.redhat.com/show_bug.cgi?id=1490344#c18

Metrics

Weaknesses (1)

CWE-416

Use After Free

References (60)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner apache
Published Sep 18, 2017
Updated Nov 4, 2025
Reserved Jun 21, 2017
Link CVE-2017-9798
CISA Vulnrichment
Updated n/a
NVD
Status Modified
Modified Jun 17, 2026
Link CVE-2017-9798
Red Hat
Severity Moderate
Public date Sep 18, 2017
Links CVE-2017-9798 - Bugzilla