Description
Stack-based buffer overflow in the parseLegacySyslogMsg function in tools/syslogd.c in rsyslogd in rsyslog 4.6.x before 4.6.8 and 5.2.0 through 5.8.4 might allow remote attackers to cause a denial of service (application exit) via a long TAG in a legacy syslog message.
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 14 | rsyslog | 5.8.5-1 | — |
| Debian 13 | rsyslog | 5.8.5-1 | — |
| Debian 12 | rsyslog | 5.8.5-1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | rsyslog +5 | 4.6.2-3.el6_1.2 | RHSA-2011:1247 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | rsyslog | 8.23.0-2.1 | openSUSE-SU-2024:10498-1 |
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.
Metasploit 1 module
-
rsyslog Long Tag Off-By-Two DoS
auxiliary/dos/syslog/rsyslog_long_tag
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- RHSA-2011:1247 Red Hat Security Advisory: rsyslog security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- openSUSE-SU-2024:10498-1 rsyslog-8.23.0-2.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- 46027 third-party-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=727644
- http://www.rsyslog.com/potential-dos-with-malformed-tag/
- 1026000 vdb-entry
- openSUSE-SU-2011:1020 vendor-advisory
- http://git.adiscon.com/?p=rsyslog.git%3Ba=commit%3Bh=1ca6cc236d1dabf1633238b873fb1c057e52f95e
- RHSA-2011:1247 vendor-advisory
- MDVSA-2011:134 vendor-advisory
- FEDORA-2011-12282 vendor-advisory
- 49413 vdb-entry
- FEDORA-2011-12250 vendor-advisory
- 45922 third-party-advisory