CVE-2021-26929

An XSS issue was discovered in Horde Groupware Webmail Edition through 5.2.22 (where the Horde_Text_Filter library before 2.3.7 is used). The attacker can send a plain text e-mail message, with JavaScript encoded as a link or email that is mishandled by preProcess in Text2html.php, because bespoke use of \x00\x00\x00 and \x01\x01\x01 interferes with XSS defenses.

• CWE-79

• http://packetstormsecurity.com/files/162187/Webmail-Edition-5.2.22-XSS-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
• http://packetstormsecurity.com/files/162194/Horde-Groupware-Webmail-5.2.22-Cross-Site-Scripting.htmlThird Party Advisory
• https://github.com/horde/webmail/releasesThird Party Advisory
• https://lists.debian.org/debian-lts-announce/2021/02/msg00028.htmlMailing List, Third Party Advisory
• https://lists.horde.org/archives/announce/2021/001298.htmlMailing List, Vendor Advisory
• https://www.alexbirnberg.com/horde-xss.htmlExploit, Third Party Advisory
• https://www.horde.org/apps/webmailVendor Advisory
• http://packetstormsecurity.com/files/162187/Webmail-Edition-5.2.22-XSS-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
• http://packetstormsecurity.com/files/162194/Horde-Groupware-Webmail-5.2.22-Cross-Site-Scripting.htmlThird Party Advisory
• https://github.com/horde/webmail/releasesThird Party Advisory
• https://lists.debian.org/debian-lts-announce/2021/02/msg00028.htmlMailing List, Third Party Advisory
• https://lists.horde.org/archives/announce/2021/001298.htmlMailing List, Vendor Advisory
• https://www.alexbirnberg.com/horde-xss.htmlExploit, Third Party Advisory
• https://www.horde.org/apps/webmailVendor Advisory

Published

Feb 14, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2021-26923An issue was discovered in Argo CD before 1.8.4. Accessing t…7.5
• CVE-2021-26924An issue was discovered in Argo CD before 1.8.4. Browser XSS…6.1
• CVE-2021-26925Roundcube before 1.4.11 allows XSS via crafted Cascading Sty…5.4
• CVE-2021-26926A flaw was found in jasper before 2.0.25. An out of bounds r…7.1
• CVE-2021-26927A flaw was found in jasper before 2.0.25. A null pointer der…5.5
• CVE-2021-26928BIRD through 2.0.7 does not provide functionality for passwo…6.8
• CVE-2021-26930An issue was discovered in the Linux kernel 3.11 through 5.1…7.8
• CVE-2021-26931An issue was discovered in the Linux kernel 2.6.39 through 5…5.5
• CVE-2021-26932An issue was discovered in the Linux kernel 3.2 through 5.10…5.5
• CVE-2021-26933An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a…5.5
• CVE-2021-26934An issue was discovered in the Linux kernel 4.18 through 5.1…7.8
• CVE-2021-26935In WoWonder < 3.1, remote attackers can gain access to the d…7.5