{"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": "2026-11-03T15:32:53.768Z"}, "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\u2019s 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\u2019s 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"}}}}

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2.3.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "HDF5", "source": "cna", "vendor": "The HDF Group"}, "product": "hdf5", "vendor": "hdfgroup"}], "created": "2026-11-03T16:45:13.733703+00:00", "updated": "2026-11-03T16:45:14.067448+00:00", "vendors": ["hdfgroup", "hdfgroup$PRODUCT$hdf5"]}