{"id":"CVE-2026-120756","aliases":["AZL-112634","DEBIAN-CVE-2026-120756","EUVD-2026-116008","GHSA-m9xj-6f2h-rx5r","UBUNTU-CVE-2026-120756"],"status":"published","title":"Heap Buffer Over-read via Malformed Message Size in HDF5's H5O__chunk_deserialize","description":"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.","severity":{"version":"4.0","score":1.9,"vector":"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","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00178,"percentile":0.07497,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-125"],"published":"2026-11-03T15:32:53Z","modified":"2026-11-05T11:47:27Z","affected":[{"source":"osv","ecosystem":"Azure Linux:3","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.14.6-6"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.10+repack-1","1.10.10+repack-2","1.10.10+repack-3","1.10.10+repack-3.1","1.10.10+repack-3.2","1.10.10+repack-3.2+ports","1.10.10+repack-3.3","1.10.10+repack-4","1.10.10+repack-5","1.10.8+repack1-1","1.12.0+repack-1~exp1","1.12.0+repack-1~exp2","1.12.2+repack-1~exp1","1.14.3+repack-1~exp1","1.14.3+repack1-1~exp2","1.14.3+repack1-1~exp3","1.14.4.3+repack-1~exp1","1.14.4.3+repack-1~exp2","1.14.4.3+repack-1~exp3","1.14.5+repack-1","1.14.5+repack-1~exp1","1.14.5+repack-1~exp2","1.14.5+repack-1~exp3","1.14.5+repack-1~exp4","1.14.5+repack-1~exp5","1.14.5+repack-1~exp6","1.14.5+repack-2","1.14.5+repack-3","1.14.5+repack-3.1","1.14.5+repack-3~exp1","1.14.5+repack-3~exp2","1.14.5+repack-3~exp3","1.14.5+repack-3~exp4","1.14.5+repack-4","1.14.5+repack-4~exp1","1.14.5+repack-4~exp2","1.14.5+repack-5~exp2","1.14.5+repack-5~exp3","1.14.6+repack-1","1.14.6+repack-1~exp1","1.14.6+repack-1~exp10","1.14.6+repack-1~exp11","1.14.6+repack-1~exp12","1.14.6+repack-1~exp13","1.14.6+repack-1~exp14","1.14.6+repack-1~exp15","1.14.6+repack-1~exp16","1.14.6+repack-1~exp17","1.14.6+repack-1~exp18","1.14.6+repack-1~exp19","1.14.6+repack-1~exp2","1.14.6+repack-1~exp20","1.14.6+repack-1~exp21","1.14.6+repack-1~exp3","1.14.6+repack-1~exp4","1.14.6+repack-1~exp5","1.14.6+repack-1~exp6","1.14.6+repack-1~exp7","1.14.6+repack-1~exp8","1.14.6+repack-1~exp9","1.14.6+repack-2","1.14.6+repack-3~exp1","2.1.0+repack-1","2.1.0+repack-1~exp10","2.1.0+repack-1~exp11","2.1.0+repack-1~exp3","2.1.0+repack-1~exp4","2.1.0+repack-1~exp5","2.1.0+repack-1~exp6","2.1.0+repack-1~exp7","2.1.0+repack-1~exp8","2.1.0+repack-1~exp9","2.2.0+repack-1","2.2.0+repack-2","2.2.0+repack-3","2.2.0+repack-4","2.2.0+repack-5","2.2.0+repack-6"]},{"source":"osv","ecosystem":"Debian:13","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.14.5+repack-3","1.14.5+repack-3.1","1.14.5+repack-4","1.14.5+repack-4~exp1","1.14.5+repack-4~exp2","1.14.5+repack-5~exp2","1.14.5+repack-5~exp3","1.14.6+repack-1","1.14.6+repack-1~exp1","1.14.6+repack-1~exp10","1.14.6+repack-1~exp11","1.14.6+repack-1~exp12","1.14.6+repack-1~exp13","1.14.6+repack-1~exp14","1.14.6+repack-1~exp15","1.14.6+repack-1~exp16","1.14.6+repack-1~exp17","1.14.6+repack-1~exp18","1.14.6+repack-1~exp19","1.14.6+repack-1~exp2","1.14.6+repack-1~exp20","1.14.6+repack-1~exp21","1.14.6+repack-1~exp3","1.14.6+repack-1~exp4","1.14.6+repack-1~exp5","1.14.6+repack-1~exp6","1.14.6+repack-1~exp7","1.14.6+repack-1~exp8","1.14.6+repack-1~exp9","1.14.6+repack-2","1.14.6+repack-3~exp1","2.1.0+repack-1","2.1.0+repack-1~exp10","2.1.0+repack-1~exp11","2.1.0+repack-1~exp3","2.1.0+repack-1~exp4","2.1.0+repack-1~exp5","2.1.0+repack-1~exp6","2.1.0+repack-1~exp7","2.1.0+repack-1~exp8","2.1.0+repack-1~exp9","2.2.0+repack-1","2.2.0+repack-2","2.2.0+repack-3","2.2.0+repack-4","2.2.0+repack-5","2.2.0+repack-6"]},{"source":"osv","ecosystem":"Debian:14","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.14.5+repack-3","1.14.5+repack-3.1","1.14.5+repack-4","1.14.5+repack-4~exp1","1.14.5+repack-4~exp2","1.14.5+repack-5~exp2","1.14.5+repack-5~exp3","1.14.6+repack-1","1.14.6+repack-1~exp1","1.14.6+repack-1~exp10","1.14.6+repack-1~exp11","1.14.6+repack-1~exp12","1.14.6+repack-1~exp13","1.14.6+repack-1~exp14","1.14.6+repack-1~exp15","1.14.6+repack-1~exp16","1.14.6+repack-1~exp17","1.14.6+repack-1~exp18","1.14.6+repack-1~exp19","1.14.6+repack-1~exp2","1.14.6+repack-1~exp20","1.14.6+repack-1~exp21","1.14.6+repack-1~exp3","1.14.6+repack-1~exp4","1.14.6+repack-1~exp5","1.14.6+repack-1~exp6","1.14.6+repack-1~exp7","1.14.6+repack-1~exp8","1.14.6+repack-1~exp9","1.14.6+repack-2","1.14.6+repack-3~exp1","2.1.0+repack-1","2.1.0+repack-1~exp10","2.1.0+repack-1~exp11","2.1.0+repack-1~exp3","2.1.0+repack-1~exp4","2.1.0+repack-1~exp5","2.1.0+repack-1~exp6","2.1.0+repack-1~exp7","2.1.0+repack-1~exp8","2.1.0+repack-1~exp9","2.2.0+repack-1","2.2.0+repack-2","2.2.0+repack-3","2.2.0+repack-4","2.2.0+repack-5","2.2.0+repack-6"]},{"source":"osv","ecosystem":"Ubuntu:Pro:14.04:LTS","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.11-3ubuntu1","1.8.11-5ubuntu1","1.8.11-5ubuntu2","1.8.11-5ubuntu6","1.8.11-5ubuntu7","1.8.11-5ubuntu7.1","1.8.11-5ubuntu7.1+esm1","1.8.11-5ubuntu7.1+esm2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.15-patch1+docs-4","1.8.15-patch1+docs-5","1.8.16+docs-1","1.8.16+docs-2","1.8.16+docs-3","1.8.16+docs-3ubuntu1","1.8.16+docs-4","1.8.16+docs-4ubuntu1","1.8.16+docs-4ubuntu1.1","1.8.16+docs-4ubuntu1.1+esm1","1.8.16+docs-4ubuntu1.1+esm2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.0-patch1+docs-4","1.10.0-patch1+docs-4ubuntu0.1~esm1","1.10.0-patch1+docs-4ubuntu0.1~esm2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.4+repack-10","1.10.4+repack-11","1.10.4+repack-11ubuntu1","1.10.4+repack-11ubuntu1+esm1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.6+repack-5","1.10.7+repack-4ubuntu1","1.10.7+repack-4ubuntu2"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.8+repack1-1ubuntu1","1.10.10+repack-3ubuntu1","1.10.10+repack-3.1ubuntu3","1.10.10+repack-3.1ubuntu4"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.14.6+repack-2","2.2.0+repack-4","2.2.0+repack-5"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"hdf5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.14.5+repack-3build1","1.14.5+repack-4","1.14.6+repack-2"]}],"products":[{"vendor":"hdfgroup","product":"hdf5"},{"vendor":"the hdf group","product":"hdf5"}],"references":[{"url":"https://github.com/HDFGroup/hdf5/pull/6589","tags":["Issue Tracking","Patch","fix","report"]},{"url":"https://github.com/HDFGroup/hdf5/issues/6401","tags":["Exploit","Vendor Advisory","Issue Tracking","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-120756","tags":["web","advisory"]},{"url":"https://github.com/advisories/GHSA-m9xj-6f2h-rx5r"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/120xxx/CVE-2026-120756.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-120756","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-120756","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-120756","tags":["report"]},{"url":"https://github.com/HDFGroup/hdf5/commit/10f1af5528168c5a71a58eba0b486e0677f3aaa3","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-120756","title":"Heap Buffer Over-read via Malformed Message Size in HDF5's H5O__chunk_deserialize","description":"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.","status":"published","published":"2026-11-03T15:32:53.768Z","modified":"2026-11-03T17:55:20.773Z","cvss":[{"version":"4.0","score":1.9,"vector":"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","level":"low","assessor":"cna"}],"cwes":["CWE-125"],"updated_at":"2026-11-03T19:01:22.66055Z"}],"euvd":[{"id":"EUVD-2026-116008","description":"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.","status":"published","published":"2026-11-03T15:32:53Z","modified":"2026-11-03T17:55:20Z","cvss":[{"version":"4.0","score":1.9,"vector":"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","level":"low"}],"updated_at":"2026-11-03T21:20:13.974366Z"}],"ghsa":[{"id":"GHSA-m9xj-6f2h-rx5r","title":"HDF5 through 2.2.0 contains a heap buffer over-read vulnerability in H5O__chunk_deserialize() in...","description":"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.","status":"published","published":"2026-11-03T18:31:01Z","modified":"2026-11-03T21:32:09Z","cvss":[{"version":"4.0","score":1.9,"vector":"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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"low"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H","level":"medium"}],"cwes":["CWE-125"],"updated_at":"2026-11-03T21:34:06.482208Z"}],"nvd":[{"id":"CVE-2026-120756","description":"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.","status":"published","published":"2026-11-03T16:17:22.94Z","modified":"2026-11-03T21:09:57.077Z","cvss":[{"version":"4.0","score":1.9,"vector":"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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"low","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H","level":"medium","assessor":"primary"}],"cwes":["CWE-125"],"updated_at":"2026-11-04T00:48:10.032782Z"}],"osv":[{"id":"CVE-2026-120756","title":"Heap Buffer Over-read via Malformed Message Size in HDF5's H5O__chunk_deserialize","description":"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.","status":"published","published":"2026-11-03T15:32:53.768Z","modified":"2026-11-05T03:30:44.410606898Z","cvss":[{"version":"4.0","score":1.9,"vector":"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","level":"low"}],"cwes":["CWE-125"],"updated_at":"2026-11-05T07:12:46.161235Z"},{"id":"DEBIAN-CVE-2026-120756","description":"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.","status":"published","published":"2026-11-03T16:17:22.94Z","modified":"2026-11-04T15:00:06.806950437Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H","level":"medium"}],"updated_at":"2026-11-04T15:03:50.387479Z"},{"id":"UBUNTU-CVE-2026-120756","description":"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.","status":"published","published":"2026-11-03T16:17:00Z","modified":"2026-11-05T11:47:27.886238693Z","cvss":[{"version":"4.0","score":1.9,"vector":"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","level":"low"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H","level":"medium"}],"updated_at":"2026-11-05T13:30:15.321876Z"},{"id":"AZL-112634","title":"CVE-2026-120756 affecting package hdf5 1.14.6-6","description":"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.","status":"published","published":"2026-11-03T16:17:22Z","modified":"2026-11-05T05:40:51Z","updated_at":"2026-11-05T16:41:19.001909Z"}]}}