CVE-2021-31618
This led to a NULL pointer dereference on initialised memory, crashing reliably the child process.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 51.5%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against the size limitations as configured for the server and used for the HTTP/1 protocol as well. On violation of these restrictions and HTTP response is sent to the client with a status code indicating why the request was rejected. This rejection response was not fully initialised in the HTTP/2 protocol handler if the offending header was the very first one received or appeared in a a footer. This led to a NULL pointer dereference on initialised memory, crashing reliably the child process. Since such a triggering HTTP/2 request is easy to craft and submit, this can be exploited to DoS the server. This issue affected mod_http2 1.15.17 and Apache HTTP Server version 2.4.47 only. Apache HTTP Server 2.4.47 was never released.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 51.49% probability · 99th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- apache/http server · fedoraproject/fedora · debian/debian linux · oracle/enterprise manager ops center · oracle/instantis enterprisetrack · oracle/zfs storage appliance kit
- Source
- security@apache.org
References
- http://httpd.apache.org/security/vulnerabilities_24.htmlRelease Notes, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2021/06/10/9Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2024/03/13/2
- https://lists.apache.org/thread.html/r14b66ef0f4f569fd515a3f96cd4eb58bd9a8ff525cc326bb0359664f%40%3Ccvs.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r783b6558abf3305b17ea462bed4bd66d82866438999bf38cef6d11d1%40%3Ccvs.httpd.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2021/07/msg00006.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2NKJ3ZA3FTSZ2QBBPKS6BYGAWYRABNQQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A73QJ4HPUMU26I6EULG6SCK67TUEXZYR/
- https://seclists.org/oss-sec/2021/q2/206Mailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202107-38Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210727-0008/Third Party Advisory
- https://www.debian.org/security/2021/dsa-4937Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
- http://httpd.apache.org/security/vulnerabilities_24.htmlRelease Notes, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2021/06/10/9Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2024/03/13/2
- https://lists.apache.org/thread.html/r14b66ef0f4f569fd515a3f96cd4eb58bd9a8ff525cc326bb0359664f%40%3Ccvs.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r783b6558abf3305b17ea462bed4bd66d82866438999bf38cef6d11d1%40%3Ccvs.httpd.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2021/07/msg00006.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2NKJ3ZA3FTSZ2QBBPKS6BYGAWYRABNQQ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A73QJ4HPUMU26I6EULG6SCK67TUEXZYR/
- https://seclists.org/oss-sec/2021/q2/206Mailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202107-38Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210727-0008/Third Party Advisory
- https://www.debian.org/security/2021/dsa-4937Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.