high CVSS 7.5

CVE-2025-53020·Apache vulnerability

Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server. This issue affects Apache HTTP Server: from 2.4.17 up to 2.4.63. Users are recommended to upgrade to version 2.4.64, which fixes the issue.

Severity
high
Software
Apache
Fixed in
2.4.64
Published
2025-07-10

Affected versions

From: 2.4.17

Until: 2.4.64

Fixed in: 2.4.64

How to fix this CVE

Apache HTTP Server versions 2.4.17 through 2.4.63 contain a use-after-free memory management flaw that can trigger denial-of-service conditions on affected web servers. Immediately upgrade to Apache 2.4.64 or later to eliminate this vulnerability and restore normal server availability. Verify the upgrade is complete by checking the version output and monitoring server logs for any residual memory-related errors.

sudo dnf update httpd

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Run `apache2 -v` (or `httpd -v` on RHEL/CentOS) and confirm the version number is between 2.4.17 and 2.4.63
  2. Step 2: Check the Apache configuration for any exposed modules or listeners by examining `/etc/apache2/apache2.conf` and enabled sites in `/etc/apache2/sites-enabled/`
  3. Step 3: Search Apache error logs with `grep -i 'segmentation\|memory\|fault' /var/log/apache2/error.log` to identify crash signatures
  4. Step 4: After upgrading, run `apache2 -v` or `httpd -v` again to confirm version is 2.4.64 or higher, then restart the service with `sudo systemctl restart apache2`

FAQ

What is CVE-2025-53020?

CVE-2025-53020 is a use-after-free memory vulnerability in Apache HTTP Server that occurs when memory is incorrectly deallocated before the end of its intended lifetime. This flaw allows remote attackers to trigger denial-of-service conditions by causing the server process to crash.

Is CVE-2025-53020 being actively exploited?

No, CVE-2025-53020 is not currently listed as actively exploited according to CISA's Known Exploited Vulnerabilities catalog, and no public exploit code is available.

What versions of Apache are affected by CVE-2025-53020?

Apache HTTP Server versions 2.4.17 through 2.4.63 are vulnerable. Version 2.4.64 and all subsequent releases include the fix.

How do I check if my server is vulnerable to CVE-2025-53020?

Run `apache2 -v` or `httpd -v` depending on your system. If the version output shows 2.4.17 to 2.4.63, your server is vulnerable and requires immediate upgrading.

Does Defensia detect CVE-2025-53020?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Apache is installed on a monitored server, CVE-2025-53020 will appear in your dashboard with remediation steps.

Related Apache CVEs

CVE-2024-38476CVSS 9.8Vulnerability in core of Apache HTTP Server 2.4.59 and earlier are vulnerably to information disclosure, SSRF or local script execution via backend applications whose response headers are malicious or exploitable. Users are recommended to upgrade to version 2.4.60, which fixes this issue.
CVE-2024-38474CVSS 9.8Substitution encoding issue in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows attacker to execute scripts in directories permitted by the configuration but not directly reachable by any URL or source disclosure of scripts meant to only to be executed as CGI. Users are recommended to upgrade to version 2.4.60, which fixes this issue. Some RewriteRules that capture and substitute unsafely will now fail unless rewrite flag "UnsafeAllow3F" is specified.
CVE-2024-38475CVSS 9.1Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to map URLs to filesystem locations that are permitted to be served by the server but are not intentionally/directly reachable by any URL, resulting in code execution or source code disclosure. Substitutions in server context that use a backreferences or variables as the first segment of the substitution are affected.  Some unsafe RewiteRules will be broken by this change and the rewrite flag "UnsafePrefixStat" can be used to opt back in once ensuring the substitution is appropriately constrained.
CVE-2025-23048CVSS 9.1In some mod_ssl configurations on Apache HTTP Server 2.4.35 through to 2.4.63, an access control bypass by trusted clients is possible using TLS 1.3 session resumption. Configurations are affected when mod_ssl is configured for multiple virtual hosts, with each restricted to a different set of trusted client certificates (for example with a different SSLCACertificateFile/Path setting). In such a case, a client trusted to access one virtual host may be able to access another virtual host, if SSLStrictSNIVHostCheck is not enabled in either virtual host.
CVE-2025-58098CVSS 8.3Apache HTTP Server 2.4.65 and earlier with Server Side Includes (SSI) enabled and mod_cgid (but not mod_cgi) passes the shell-escaped query string to #exec cmd="..." directives. This issue affects Apache HTTP Server before 2.4.66. Users are recommended to upgrade to version 2.4.66, which fixes the issue.

References

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