high CVSS 7.5

CVE-2024-38477·Apache vulnerability

null pointer dereference in mod_proxy in Apache HTTP Server 2.4.59 and earlier allows an attacker to crash the server via a malicious request. Users are recommended to upgrade to version 2.4.60, which fixes this issue.

Severity
high
Software
Apache
Fixed in
2.4.60
Published
2024-07-01

Affected versions

From: 2.4.0

Until: 2.4.60

Fixed in: 2.4.60

How to fix this CVE

Apache HTTP Server versions 2.4.59 and earlier contain a null pointer dereference vulnerability in the mod_proxy module that can be triggered by specially crafted requests, leading to service denial. Immediately upgrade to Apache 2.4.60 or later to patch this flaw. If immediate patching is not feasible, disable the mod_proxy module or restrict access to affected proxy endpoints using firewall rules.

sudo dnf update httpd httpd-tools

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check installed Apache version with 'apache2ctl -v' or 'httpd -v' and confirm it is 2.4.60 or later
  2. Step 2: Verify mod_proxy is enabled by running 'apache2ctl -M | grep proxy' and note if proxy_module is loaded
  3. Step 3: Search Apache error logs for segmentation faults or crashes: 'grep -i "segmentation\|seg fault\|null pointer" /var/log/apache2/error.log'
  4. Step 4: After patching, restart Apache with 'sudo systemctl restart apache2' and confirm it stays running for at least 5 minutes under normal load

FAQ

What is CVE-2024-38477?

This vulnerability is a null pointer dereference in Apache's mod_proxy module that occurs when processing malformed proxy requests. An unauthenticated attacker can send a specially crafted HTTP request to cause the Apache process to crash, resulting in denial of service.

Is CVE-2024-38477 being actively exploited?

No, according to CISA's Known Exploited Vulnerabilities catalog, this CVE is not currently being exploited in the wild. However, proof-of-concept information is publicly available, so patching should not be delayed.

What versions of Apache are affected by CVE-2024-38477?

Apache HTTP Server versions 2.4.0 through 2.4.59 are vulnerable. Version 2.4.60 and later include the fix.

How do I check if my server is vulnerable to CVE-2024-38477?

Run 'apache2ctl -v' or 'httpd -v' to display your Apache version. If it shows 2.4.59 or earlier and 'apache2ctl -M | grep proxy_module' returns a match, your server is vulnerable.

Does Defensia detect CVE-2024-38477?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Apache is installed on a monitored server, CVE-2024-38477 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

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2024-38477. Free for 1 server.

Get started free