What’s Vulnerable › Vulnerabilities

CVE-2021-41524: null pointer dereference in h2 fuzzing

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 25.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-05 · updated 2026-06-17
• Weakness: CWE-476

Description

While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request processing, allowing an external source to DoS the server. This requires a specially crafted request. The vulnerability was recently introduced in version 2.4.49. No exploit is known to the project.

Affected products

• Apache HTTP Server: 2.4.49
• Fedoraproject Fedora: 34, 35
• NetApp Cloud Backup: all versions
• Oracle Instantis Enterprisetrack: 17.1, 17.2, 17.3

References

• http://www.openwall.com/lists/oss-security/2021/10/05/1
• https://httpd.apache.org/security/vulnerabilities_24.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DSM6UWQICBJ2TU727RENU3HBKEAFLT6T/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EUVJVRJRBW5QVX4OY3NOHZDQ3B3YOTSG/
• https://security.gentoo.org/glsa/202208-20
• https://security.netapp.com/advisory/ntap-20211029-0009/
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ
• https://www.oracle.com/security-alerts/cpujan2022.html
• http://www.openwall.com/lists/oss-security/2021/10/05/1
• https://httpd.apache.org/security/vulnerabilities_24.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DSM6UWQICBJ2TU727RENU3HBKEAFLT6T/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EUVJVRJRBW5QVX4OY3NOHZDQ3B3YOTSG/

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