{"id":"CVE-2026-61548","state":"PUBLISHED","title":"Rsyslog: mmpstrucdata stack buffer overflow with oversized RFC5424 structured data","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.","publishedAt":"2026-09-18T16:54:28.925Z","updatedAt":"2026-09-21T20:49:39.195Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["rsyslog rsyslog"],"affected":[{"vendor":"rsyslog","product":"rsyslog","versions":[{"version":">= 7.5.4, < 8.2606.0","status":"affected"}]}],"references":["https://github.com/rsyslog/rsyslog/security/advisories/GHSA-8qmr-c66f-g368","https://github.com/rsyslog/rsyslog/pull/6991","https://github.com/rsyslog/rsyslog/commit/bcda60a3692efdf0c8e44102528f5a0ebe0dec6d","https://github.com/rsyslog/rsyslog/releases/tag/v8.2606.0","http://www.openwall.com/lists/oss-security/2026/07/20/1"],"weaknesses":["CWE-121"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/61xxx/CVE-2026-61548.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-61548","state":"PUBLISHED","datePublished":"2026-09-18T16:54:28.925Z","dateUpdated":"2026-09-21T20:49:39.195Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-10T16:27:03.094Z"},"containers":{"cna":{"title":"Rsyslog: mmpstrucdata stack buffer overflow with oversized RFC5424 structured data","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"rsyslog","product":"rsyslog","versions":[{"version":">= 7.5.4, < 8.2606.0","status":"affected"}]}],"references":[{"url":"https://github.com/rsyslog/rsyslog/security/advisories/GHSA-8qmr-c66f-g368","name":"https://github.com/rsyslog/rsyslog/security/advisories/GHSA-8qmr-c66f-g368","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/rsyslog/rsyslog/pull/6991","name":"https://github.com/rsyslog/rsyslog/pull/6991","tags":["x_refsource_MISC"]},{"url":"https://github.com/rsyslog/rsyslog/commit/bcda60a3692efdf0c8e44102528f5a0ebe0dec6d","name":"https://github.com/rsyslog/rsyslog/commit/bcda60a3692efdf0c8e44102528f5a0ebe0dec6d","tags":["x_refsource_MISC"]},{"url":"https://github.com/rsyslog/rsyslog/releases/tag/v8.2606.0","name":"https://github.com/rsyslog/rsyslog/releases/tag/v8.2606.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-121","lang":"en","description":"CWE-121: Stack-based Buffer Overflow","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-18T16:54:28.925Z"},"source":{"advisory":"GHSA-8qmr-c66f-g368","discovery":"UNKNOWN"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/07/20/1"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-09-18T17:11:33.491Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-18T19:24:39.206415Z","id":"CVE-2026-61548","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-21T20:49:39.195Z"}}]}}}