medium CVSS 4.3

CVE-2026-42528·Apache vulnerability

A memory calculation bug in mod_dav in Apache httpd 2.4.67 and earlier allows an attacker with permission to create WebDAV locks to crash server child processes. Users are recommended to upgrade to version 2.4.69, which fixes this issue

Severity
medium
Software
Apache
Fixed in
2.4.69
Published
2026-10-01

Affected versions

From: 2.4.60

Until: 2.4.69

Fixed in: 2.4.69

How to fix this CVE

Organizations running Apache httpd versions 2.4.60 through 2.4.68 should immediately upgrade to version 2.4.69 or later to patch a memory calculation flaw in the mod_dav module. This vulnerability can be exploited by authenticated users with WebDAV lock creation privileges to trigger denial-of-service conditions through child process crashes. Prioritize this update for production web servers that expose WebDAV functionality.

sudo dnf update httpd

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'apache2ctl -v' or 'httpd -v' to display the currently installed Apache version and confirm if it falls within the 2.4.60-2.4.68 range
  2. Execute 'apache2ctl -M | grep dav' (or 'httpd -M | grep dav') to verify whether mod_dav is loaded and active on the server
  3. Search Apache access and error logs for WebDAV LOCK request patterns: grep -i 'LOCK' /var/log/apache2/access.log or equivalent error log path
  4. After patching, re-run 'apache2ctl -v' to confirm the version is 2.4.69 or higher, and restart Apache with 'sudo systemctl restart apache2' to apply changes

FAQ

What is CVE-2026-42528?

CVE-2026-42528 is a memory calculation vulnerability in Apache httpd's mod_dav module that allows authenticated users with WebDAV lock creation permissions to crash server worker processes, resulting in denial of service. The flaw stems from incorrect memory size computations when processing lock-related operations.

Is CVE-2026-42528 being actively exploited?

No, this vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, and no public exploits are available. However, the attack requires only authenticated access to WebDAV, making it a practical threat in environments where untrusted users have such permissions.

What versions of Apache are affected by CVE-2026-42528?

Apache httpd versions 2.4.60 through 2.4.68 are vulnerable. Version 2.4.69 and later contain the fix. Earlier versions (2.4.59 and below) are not affected.

How do I check if my server is vulnerable to CVE-2026-42528?

Run 'httpd -v' or 'apache2ctl -v' and check if the version output is between 2.4.60 and 2.4.68. If mod_dav is loaded (verify with 'httpd -M | grep dav'), and the version is in the vulnerable range, your server is at risk.

Does Defensia detect CVE-2026-42528?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Apache is installed on a monitored server, CVE-2026-42528 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-2026-28780CVSS 9.8Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server. If mod_proxy_ajp connects to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause it to write 4 attacker controlled bytes after the end of a heap based buffer. This issue affects Apache HTTP Server: through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.
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-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.

References

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