CVE-2021-26929 EXPLOIT
6.1
MEDIUM · CVSS 3.1 · EPSS 4.9% (pctl 92)
Patch early
A public exploit exists.
Description
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.
Scoring
| CVSS | 6.1 (MEDIUM, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| EPSS | 4.94% — more likely to be exploited than 92% of all CVEs |
| Weakness | CWE-79 |
| On CISA KEV | no |
| Public exploit | yes |
| Published | 2021-02-14 |
| Last modified | 2026-06-17 |
Affected (2)
| Vendor | Product |
|---|---|
| debian | debian linux |
| horde | groupware |
Public exploits
| Source | Title | Date |
|---|---|---|
| exploit-db | Horde Groupware Webmail 5.2.22 - Stored XSS | 2021-04-15 |
References
- http://packetstormsecurity.com/files/162187/Webmail-Edition-5.2.22-XSS-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/162194/Horde-Groupware-Webmail-5.2.22-Cross-Site-Scripting.html
- https://github.com/horde/webmail/releases
- https://lists.debian.org/debian-lts-announce/2021/02/msg00028.html
- https://lists.horde.org/archives/announce/2021/001298.html
- https://www.alexbirnberg.com/horde-xss.html
- https://www.horde.org/apps/webmail
- http://packetstormsecurity.com/files/162187/Webmail-Edition-5.2.22-XSS-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/162194/Horde-Groupware-Webmail-5.2.22-Cross-Site-Scripting.html
- https://github.com/horde/webmail/releases
- https://lists.debian.org/debian-lts-announce/2021/02/msg00028.html
- https://lists.horde.org/archives/announce/2021/001298.html
- https://www.alexbirnberg.com/horde-xss.html
- https://www.horde.org/apps/webmail
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