CVE-2021-26691
CRITICAL9.8EPSS 47.8%Apache HTTP Server mod_session response handling heap overflow
Published: 6/10/2021Modified: 4/28/2026
Description
In Apache HTTP Server versions 2.4.0 to 2.4.46 a specially crafted SessionHeader sent by an origin server could cause a heap overflow
Affected packages (3)
- Alpine/apache2from 0, < 2.4.48-r0
- Bitnami/apache>= 2.4.0, < 2.4.47
- Debian/apache2from 0, < 2.4.46-6
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
References (16)
- ADVISORYhttps://security.alpinelinux.org/vuln/CVE-2021-26691
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-26691
- WEBhttp://httpd.apache.org/security/vulnerabilities_24.html
- WEBhttps://lists.apache.org/thread.html/r50cae1b71f1e7421069036b213c26da7d8f47dd59874e3bd956959fe%40%3Cannounce.httpd.apache.org%3E
- WEBhttps://lists.apache.org/thread.html/r7f2b70b621651548f4b6f027552f1dd91705d7111bb5d15cda0a68dd%40%3Cdev.httpd.apache.org%3E
- WEBhttps://lists.apache.org/thread.html/re026d3da9d7824bd93b9f871c0fdda978d960c7e62d8c43cba8d0bf3%40%3Ccvs.httpd.apache.org%3E
- WEBhttps://lists.debian.org/debian-lts-announce/2021/07/msg00006.html
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
- WEBhttps://nvd.nist.gov/vuln/detail/CVE-2021-26691
- WEBhttps://security.gentoo.org/glsa/202107-38
- WEBhttps://security.netapp.com/advisory/ntap-20210702-0001/
- WEBhttps://www.debian.org/security/2021/dsa-4937
- WEBhttps://www.oracle.com/security-alerts/cpujan2022.html
- WEBhttps://www.oracle.com/security-alerts/cpuoct2021.html
- WEBhttp://www.openwall.com/lists/oss-security/2021/06/10/7