| Name | CVE-2026-61548 |
| Description | Rsyslog is a rocket-fast system for log processing. From 7.5.4 until 8.2606.0, the optional mmpstrucdata plugin's parseSD_PARAM function in plugins/mmpstrucdata/mmpstrucdata.c stores RFC5424 parameter values in a fixed pVal[32 * 1024] stack buffer and calls parsePARAM_VALUE without supplying the destination size. A remote unauthenticated attacker whose crafted RFC5424 message reaches an action using mmpstrucdata can provide a structured-data parameter larger than that buffer when MaxMessageSize permits it, causing an attacker-controlled stack overwrite. Deployments that do not install and use the plugin, or whose effective message-size limit remains below the required threshold, are not affected by this issue. The demonstrated impact is a crash and interruption of log collection; code execution is not demonstrated. This issue is fixed in version 8.2606.0. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| rsyslog (PTS) | bookworm | 8.2302.0-1+deb12u1 | vulnerable |
| trixie | 8.2504.0-1+deb13u2 | fixed |
| forky, sid | 8.2608.0-4 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| rsyslog | source | trixie | 8.2504.0-1+deb13u2 | | | |
| rsyslog | source | (unstable) | 8.2606.0-4 | | | |
Notes
[bookworm] - rsyslog <postponed> (mmpstrucdata module, opt-in; needs module loaded + oversized RFC5424 structured-data)
[bullseye] - rsyslog <postponed> (mmpstrucdata module, opt-in; needs module loaded + oversized RFC5424 structured-data)
https://www.openwall.com/lists/oss-security/2026/07/20/1
https://github.com/rsyslog/rsyslog/security/advisories/GHSA-8qmr-c66f-g368
Fixed in major cleanup and refactoring of mmpstrucdata:
https://github.com/rsyslog/rsyslog/pull/6991