high CVSS 7.5

CVE-2026-46729·Apache vulnerability

NULL Pointer Dereference vulnerability in Apache HTTP Servers mod_heartmonitor over unicast listener. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.

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

Affected versions

From: 2.4.0

Until: 2.4.69

Fixed in: 2.4.69

How to fix this CVE

Upgrade Apache HTTP Server to version 2.4.69 or later to resolve a null pointer dereference flaw in the mod_heartmonitor module that can cause denial of service. Organizations running versions 2.4.60 through 2.4.68 should prioritize this update, especially if heartbeat monitoring over unicast listeners is enabled in their configuration. After patching, restart the Apache service and verify the new version is running.

sudo dnf update httpd && sudo systemctl restart httpd

Defensia detects this vulnerability

How to check if you are affected

  1. Check the current Apache version: apache2ctl -v (Ubuntu/Debian) or httpd -v (RHEL/CentOS)
  2. Verify if mod_heartmonitor is loaded: grep -i heartmonitor /etc/apache2/mods-enabled/* or grep -i heartmonitor /etc/httpd/conf.modules.d/*
  3. Search Apache error logs for segmentation faults or null pointer errors: grep -i 'segmentation\|null pointer\|heartmonitor' /var/log/apache2/error.log or /var/log/httpd/error_log
  4. Confirm the patch by re-running apache2ctl -v or httpd -v and verifying the version is 2.4.69 or later

FAQ

What is CVE-2026-46729?

CVE-2026-46729 is a null pointer dereference vulnerability in Apache's mod_heartmonitor module that occurs when processing unicast listener traffic, allowing remote attackers to crash the web server and cause a denial of service condition.

Is CVE-2026-46729 being actively exploited?

No, this vulnerability is not currently listed as actively exploited in the CISA Known Exploited Vulnerabilities catalog, and no public proof-of-concept exploits are available.

What versions of Apache are affected by CVE-2026-46729?

Apache HTTP Server versions 2.4.60 through 2.4.68 are vulnerable. Version 2.4.69 and later contain the fix.

How do I check if my server is vulnerable to CVE-2026-46729?

Run 'apache2ctl -v' or 'httpd -v' and check if the version is between 2.4.60 and 2.4.68. If mod_heartmonitor is enabled (check with 'grep heartmonitor /etc/apache2/mods-enabled/*'), your server is at risk.

Does Defensia detect CVE-2026-46729?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Apache is installed on a monitored server, CVE-2026-46729 will appear in your dashboard with remediation steps.

Related Apache CVEs

CVE-2021-41773CVSS 10A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found to be incomplete, see CVE-2021-42013.
CVE-2021-42013CVSS 10It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution. This issue only affects Apache 2.4.49 and Apache 2.4.50 and not earlier versions.
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-2024-38476CVSS 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-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.

References

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