# CVE-2026-61548: Rsyslog: mmpstrucdata stack buffer overflow with oversized RFC5424 structured data > Remote attackers can cause a denial of service in Rsyslog by sending oversized RFC5424 messages to the optional mmpstrucdata plugin. - **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 18 Sep 2026 - **Updated:** 21 Sep 2026 - **Also known as:** AZL-103314, DEBIAN-CVE-2026-61548, GHSA-8qmr-c66f-g368, SUSE-SU-2026:23122-1, SUSE-SU-2026:23145-1, SUSE-SU-2026:3442-1, SUSE-SU-2026:3478-1, SUSE-SU-2026:3498-1, SUSE-SU-2026:3518-1, UBUNTU-CVE-2026-61548, USN-8598-1, openSUSE-SU-2026:11407-1, openSUSE-SU-2026:21535-1 ## What is CVE-2026-61548? CVE-2026-61548 is a high-severity memory corruption vulnerability in rsyslog, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official 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. Weakness: CWE-121 (Stack-based Buffer Overflow) ## Which versions are affected by CVE-2026-61548? | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `rsyslog` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise Module for Basesystem 15 SP7 | All versions | 8.2406.0-150700.3.7.1 | | `rsyslog` | SUSE:Linux Enterprise Module for Package Hub 15 SP7 | All versions | 8.2406.0-150700.3.7.1 | | `rsyslog` | SUSE:Linux Enterprise Module for Server Applications 15 SP7 | All versions | 8.2406.0-150700.3.7.1 | | `rsyslog` | SUSE:Linux Enterprise Server 12 SP5-LTSS | All versions | 8.2106.0-8.22.1 | | `rsyslog` | SUSE:Linux Enterprise Server 15 SP4-LTSS | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise Server 15 SP5-LTSS | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise Server 15 SP6-LTSS | All versions | 8.2406.0-150600.12.16.1 | | `rsyslog` | SUSE:Linux Enterprise Server 16.0 | All versions | 8.2502.0-160000.4.1 | | `rsyslog` | SUSE:Linux Enterprise Server 16.0 | All versions | 8.2502.0-160000.4.1 | | `rsyslog` | SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | All versions | 8.2106.0-8.22.1 | | `rsyslog` | SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | All versions | 8.2306.0-150400.5.40.1 | | `rsyslog` | SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | All versions | 8.2406.0-150600.12.16.1 | | `rsyslog` | SUSE:Linux Enterprise Server for SAP applications 16.0 | All versions | 8.2502.0-160000.4.1 | | `rsyslog` | SUSE:Linux Enterprise Server for SAP applications 16.0 | All versions | 8.2502.0-160000.4.1 | | `rsyslog` | openSUSE:Leap 16.0 | All versions | 8.2502.0-160000.4.1 | | `rsyslog` | openSUSE:Tumbleweed | All versions | 8.2606.0-1.1 | ## How do I fix CVE-2026-61548? Upgrade to a fixed version. ## Is CVE-2026-61548 being exploited? There is no known exploitation of CVE-2026-61548 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-61548 and fix it if it is affected. What it is: CVE-2026-61548 is a high-severity memory corruption vulnerability in rsyslog, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-61548 in the wild and no public exploit code. Affected product: rsyslog. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-61548/ (Markdown: https://insights.sbomify.com/CVE-2026-61548/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61548 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61548 - OSV: https://osv.dev/vulnerability/CVE-2026-61548 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-61548/ Summaries are generated and may contain mistakes; the official description above is the record.