{"id":"CVE-2026-120758","kind":"vulnerability","aliases":["CVE-2026-120758"],"related":[],"title":"HDF5: crafted file triggers NULL pointer crash when opened","description":"HDF5 through 2.2.0 contains a NULL pointer dereference vulnerability in H5HL_unprotect() in src/H5HL.c. H5HL_protect() pins a single metadata cache entry for a local heap, either the heap prefix or the separate data block, and H5HL_unprotect() unpins it on the final unprotect. When the metadata cache destroys a corrupted local heap entry, H5HL__prfx_dest() unlinks it from the heap by setting heap->prfx or heap->dblk to NULL. A crafted HDF5 file can therefore reach H5HL_unprotect() with no cached object to unpin, and the function passes the NULL pointer to H5AC_unpin_entry(). This causes an assertion failure in debug builds and a NULL pointer dereference and crash in release builds. An attacker who can get a user or application to open and traverse a malicious file can cause a denial of service.","summary":"A crafted HDF5 file makes the HDF5 library dereference a NULL pointer in H5HL_unprotect() while reading a corrupted local heap. The result is a crash, a denial of service for any program that opens and traverses the file.","severity":"medium","cvss":5.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["c","hdf5","package","python","scientific-computing"],"not_affected_if":["no-hdf5-library-in-use","trusted-files-only"],"how_to_check":"- Check the HDF5 library version in use, for example with `h5dump --version` or the version reported by your build; versions through `2.2.0` are affected.\n- Find where your applications open HDF5 files from untrusted sources.","fix":null,"status":"open","published_at":"2026-11-03T16:17:23+00:00","first_seen_at":"2026-11-03T16:21:43+00:00","triaged_at":"2026-11-03T16:24:18+00:00","updated_at":"2026-11-03T16:24:18+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-03T16:24:18Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"HDF5: crafted file triggers NULL pointer crash when opened","impact":"low","summary":"A crafted HDF5 file makes the HDF5 library dereference a NULL pointer in H5HL_unprotect() while reading a corrupted local heap. The result is a crash, a denial of service for any program that opens and traverses the file.","audience":"developers","category":"package","nicknames":[],"who_cares":["hdf5","c","python","scientific-computing"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"Crash of the process reading the malicious file, denial of service","analyst_note":"","how_to_check":"- Check the HDF5 library version in use, for example with `h5dump --version` or the version reported by your build; versions through `2.2.0` are affected.\n- Find where your applications open HDF5 files from untrusted sources.","plain_action":"","needs_analyst":false,"not_affected_if":["trusted-files-only","no-hdf5-library-in-use"],"who_is_affected":"Any application that links the HDF5 library through version 2.2.0 and opens HDF5 files that may be attacker-supplied can crash when a malicious file is traversed. Applications that only read trusted, locally produced HDF5 files are much less exposed. The sources do not state a fixed version.","user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.000685,"input_tokens":4340,"output_tokens":502,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-120758':12A,15A '-2026':11A,14A '2.2.0':64C 'applic':185C 'assert':162C 'attack':178C 'block':96C 'build':166C,176C 'c':16B 'cach':82C,109C,144C 'caus':160C,194C 'comput':22B 'contain':65C 'corrupt':41B,112C 'craft':2A,24B,134C 'crash':7A,48B,173C 'cve':10A,13A 'data':95C 'dblk':130C 'debug':165C 'denial':50B,196C 'derefer':31B,69C,171C 'dest':118C 'destroy':110C 'either':88C 'entri':83C,115C,158C 'failur':163C 'file':3A,26B,61B,136C,192C 'final':104C 'function':150C 'get':181C 'h5ac':156C 'h5hl':36B,72C,76C,98C,116C,140C 'hdf5':1A,17B,25B,29B,62C,135C 'heap':43B,87C,90C,114C,123C,126C,129C 'librari':30B 'local':42B,86C,113C 'make':27B 'malici':191C 'metadata':81C,108C 'null':5A,33B,67C,132C,153C,169C 'object':145C 'open':9A,57B,187C 'packag':18B 'pass':151C 'pin':78C 'pointer':6A,34B,68C,154C,170C 'prefix':91C 'prfx':117C,127C 'program':55B 'protect':77C 'python':19B 'reach':139C 'read':39B 'releas':175C 'result':45B 'scientif':21B 'scientific-comput':20B 'separ':94C 'servic':52B,198C 'set':125C 'singl':80C 'src/h5hl.c':75C 'therefor':138C 'travers':59B,189C 'trigger':4A 'unlink':119C 'unpin':100C,147C,157C 'unprotect':37B,73C,99C,105C,141C 'user':183C 'vulner':70C","nicknames":[],"mitigations":[],"who_affected":"Any application that links the HDF5 library through version 2.2.0 and opens HDF5 files that may be attacker-supplied can crash when a malicious file is traversed. Applications that only read trusted, locally produced HDF5 files are much less exposed. The sources do not state a fixed version.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["c","hdf5","medium","package","python","scientificcomputing"],"campaign_type":null,"first_public_at":"2026-11-03T16:17:23+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/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","cvss_by":"0253b833-3e77-4dfe-9d57-17db1a2f0a74","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-120758","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-120758","severity":null,"published_at":"2026-11-03T16:17:23+00:00","modified_at":"2026-11-03T16:17:23+00:00","first_seen_at":"2026-11-03T16:21:43+00:00","fetched_at":"2026-11-03T16:21:43+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}