{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-120756","assignerOrgId":"0253b833-3e77-4dfe-9d57-17db1a2f0a74","state":"PUBLISHED","assignerShortName":"HDFG","dateReserved":"2026-11-02T21:30:11.241Z","datePublished":"2026-11-03T15:32:53.768Z","dateUpdated":"2026-11-03T17:55:20.773Z"},"containers":{"cna":{"providerMetadata":{"orgId":"0253b833-3e77-4dfe-9d57-17db1a2f0a74","shortName":"HDFG","dateUpdated":"2026-11-03T15:32:53.768Z"},"title":"Heap Buffer Over-read via Malformed Message Size in HDF5's H5O__chunk_deserialize","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-125","description":"CWE-125 Out-of-bounds read","type":"CWE"}]}],"impacts":[{"capecId":"CAPEC-540","descriptions":[{"lang":"en","value":"CAPEC-540 Overread Buffers"}]}],"affected":[{"vendor":"The HDF Group","product":"HDF5","modules":["Object Header"],"versions":[{"status":"affected","version":"< 2.3.0"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"HDF5 through 2.2.0 contains a heap buffer over-read vulnerability in H5O__chunk_deserialize() in src/H5Ocache.c. When decoding object header messages, the declared message size is checked against the end of the chunk image before the remainder of the message header (flags, and for version 2 object headers, the optional creation index) has been decoded. Because the message body begins after these fields, a message can start up to four bytes further into the chunk than the size check accounts for. A crafted HDF5 file can declare a message size that passes the check but extends past the end of the chunk image, causing the message’s decode callback, for example H5O__mtime_new_decode() in src/H5Omtime.c, to read beyond the heap allocation. The flaw is reachable during H5Fopen() on a crafted file. An attacker who can get a user or application to open a malicious file can cause a denial of service or limited disclosure of process memory.","supportingMedia":[{"type":"text/html","base64":false,"value":"HDF5 through 2.2.0 contains a heap buffer over-read vulnerability in <code>H5O__chunk_deserialize()</code> in <code>src/H5Ocache.c</code>. When decoding object header messages, the declared message size is checked against the end of the chunk image before the remainder of the message header (flags, and for version 2 object headers, the optional creation index) has been decoded. Because the message body begins after these fields, a message can start up to four bytes further into the chunk than the size check accounts for. A crafted HDF5 file can declare a message size that passes the check but extends past the end of the chunk image, causing the message’s decode callback, for example <code>H5O__mtime_new_decode()</code> in <code>src/H5Omtime.c</code>, to read beyond the heap allocation. The flaw is reachable during <code>H5Fopen()</code> on a crafted file. An attacker who can get a user or application to open a malicious file can cause a denial of service or limited disclosure of process memory.&nbsp;&nbsp;"}]}],"references":[{"url":"https://github.com/HDFGroup/hdf5/pull/6589"},{"url":"https://github.com/HDFGroup/hdf5/issues/6401"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"LOW","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subAvailabilityImpact":"NONE","exploitMaturity":"PROOF_OF_CONCEPT","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"LOW","baseScore":1.9,"vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:P"}}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-11-03T17:55:08.252551Z","id":"CVE-2026-120756","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-11-03T17:55:20.773Z"}}]}}