Description
CRLF injection vulnerability in layers_toggle.php in WebCalendar 1.0.1 might allow remote attackers to modify HTTP headers and conduct HTTP response splitting attacks via the ret parameter, which is used to redirect URL requests.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 3.1 | webcalendar | 0.9.45-4sarge3 | DSA-1002-1 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- WebCalendar 1.0.1 - 'Layers_Toggle.php' HTTP Response Splitting EDB-26691 · webapps · Dec 1, 2005 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 1
- DSA-1002-1 webcalendar - several Debian Security (DSA / DLA) · Mar 9, 2026
References
- 20051201 WebCalendar Multiple Vulnerabilities. mailing-list
- 15673 vdb-entry
- ADV-2005-2702 vdb-entry
- 19240 third-party-advisory
- http://vd.lwang.org/webcalendar_multiple_vulns.txt
- 21383 vdb-entry
- 17848 third-party-advisory
- DSA-1002 vendor-advisory