CVE-2024-47252: Apache HTTP Server: mod_ssl error log variable escaping

Published Jun 24, 2025
·
Updated

Insufficient escaping of user-supplied data in modssl in Apache HTTP Server 2.4.63 and earlier allows an untrusted SSL/TLS client to insert escape characters into log files in some configurations.

Affected Software

5 affected componentsFixes available
Apache HTTP Server<2.4.63
Apache HTTP Server>=2.4.0<2.4.64
debian/apache2<=2.4.62-1~deb11u1
2.4.67-1~deb11u12.4.67-1~deb12u22.4.67-1~deb13u22.4.67-1
IBM DS8A00( R10.0 - R10.1 )<=10.1.3.0 - 10.10.106.1
IBM DS8900F ( R9.4)<=89.40.83.0-89.44.5.0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade debian/apache2 to a version that resolves this vulnerability.

    Fixed in 2.4.67-1~deb11u1Fixed in 2.4.67-1~deb12u2Fixed in 2.4.67-1~deb13u2Fixed in 2.4.67-1
  2. Upgrade

    Upgrade Apache HTTP Server (mod_ssl) to a version that resolves this vulnerability.

    Fixed in 2.4.63Patch CVE-2024-47252
  3. Configuration

    Avoid logging mod_ssl-provided variables such as SSL_TLS_SNI via CustomLog with the "%{varname}x" or "%{varname}c" format, since neither mod_log_config nor mod_ssl performs escaping for these variables in affected configurations (CVE-2024-47252).

    Apache httpd mod_log_config (CustomLog) CustomLog format strings using "%{varname}x" or "%{varname}c" for mod_ssl variables (e.g., SSL_TLS_SNI) = Do not use %{varname}x/%{varname}c directly with client-controlled mod_ssl variables in CustomLog; use a logging format that does not output unsanitized client-provided data

Event History

Jun 24, 2025
Data Sourced
via Red Hat·01:15 PM
DescriptionSeverityAffected Software
Jul 10, 2025
CVE Published
via MITRE·04:55 PM
Data Sourced
via MITRE·04:55 PM
DescriptionWeakness
Data Sourced
via NVD·05:15 PM
DescriptionSeverityWeaknessAffected Software
Dec 18, 2025
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software
May 28, 2026
Data Sourced
via Ubuntu·06:16 PM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Debian·06:16 PM
DescriptionAffected Software
Data Sourced
via Launchpad·06:17 PM
Description

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2024-47252?

CVE-2024-47252 has been classified as a moderate severity vulnerability.

2

How do I fix CVE-2024-47252?

To fix CVE-2024-47252, upgrade to Apache HTTP Server version 2.4.64 or later, which includes patches for this vulnerability.

3

What impact does CVE-2024-47252 have on my Apache server?

CVE-2024-47252 allows untrusted SSL/TLS clients to manipulate log files, potentially leading to misleading information in logs.

4

What versions of Apache HTTP Server are affected by CVE-2024-47252?

CVE-2024-47252 affects Apache HTTP Server versions 2.4.63 and earlier.

5

Is CVE-2024-47252 related to SSL/TLS security?

Yes, CVE-2024-47252 involves insufficient escaping of user-supplied data in the context of SSL/TLS clients.

Contact

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