{"id":"CVE-2026-41503","state":"PUBLISHED","title":"BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Property Decoder via Deprecated Tag Parser","description":"BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service property decoder allows unauthenticated remote attackers to read past allocated buffer boundaries by sending an RPM request with a truncated property list. The vulnerability stems from rpm_decode_object_property() calling the deprecated decode_tag_number_and_value() function at src/bacnet/rpm.c:344, which accepts no buffer length parameter and reads blindly from whatever pointer it receives. A crafted BACnet/IP packet with a 1-byte property payload containing an extended tag marker (0xF9) causes the decoder to read 1 byte past the end of the buffer, leading to crashes on embedded BACnet devices. The vulnerability exists in src/bacnet/rpm.c and affects any deployment that enables the ReadPropertyMultiple confirmed service handler (enabled by default in the reference server). This vulnerability is fixed in 1.4.3.","publishedAt":"2026-04-24T19:41:44.071Z","updatedAt":"2026-04-27T13:39:56.518Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["bacnet-stack bacnet-stack"],"affected":[{"vendor":"bacnet-stack","product":"bacnet-stack","versions":[{"version":">= 1.4.0, < 1.4.3","status":"affected"}]}],"references":["https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-5w2v-mwqj-pr2c"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/41xxx/CVE-2026-41503.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-41503","state":"PUBLISHED","datePublished":"2026-04-24T19:41:44.071Z","dateUpdated":"2026-04-27T13:39:56.518Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-20T18:18:50.680Z"},"containers":{"cna":{"title":"BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Property Decoder via Deprecated Tag Parser","descriptions":[{"lang":"en","value":"BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service property decoder allows unauthenticated remote attackers to read past allocated buffer boundaries by sending an RPM request with a truncated property list. The vulnerability stems from rpm_decode_object_property() calling the deprecated decode_tag_number_and_value() function at src/bacnet/rpm.c:344, which accepts no buffer length parameter and reads blindly from whatever pointer it receives. A crafted BACnet/IP packet with a 1-byte property payload containing an extended tag marker (0xF9) causes the decoder to read 1 byte past the end of the buffer, leading to crashes on embedded BACnet devices. The vulnerability exists in src/bacnet/rpm.c and affects any deployment that enables the ReadPropertyMultiple confirmed service handler (enabled by default in the reference server). This vulnerability is fixed in 1.4.3."}],"affected":[{"vendor":"bacnet-stack","product":"bacnet-stack","versions":[{"version":">= 1.4.0, < 1.4.3","status":"affected"}]}],"references":[{"url":"https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-5w2v-mwqj-pr2c","name":"https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-5w2v-mwqj-pr2c","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","description":"CWE-125: Out-of-bounds Read","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-24T19:41:44.071Z"},"source":{"advisory":"GHSA-5w2v-mwqj-pr2c","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-5w2v-mwqj-pr2c","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-27T13:39:52.930841Z","id":"CVE-2026-41503","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-27T13:39:56.518Z"}}]}}}