{"id":"CVE-2026-122330","kind":"vulnerability","aliases":["CVE-2026-122330"],"related":[],"title":"Blosc c-blosc2: crafted frame crashes applications via divide-by-zero","description":"Blosc c-blosc2 before 3.5.0 contains a divide-by-zero vulnerability in blosc2_schunk_get_slice_buffer() in blosc/schunk.c that allows attackers to crash applications by supplying crafted frames with unchecked zero chunksize or blocksize values. Attackers can provide a malicious Blosc2 frame opened via blosc2_schunk_open() or blosc2_schunk_from_buffer() and read as a slice, raising SIGFPE and terminating the process.","summary":"Blosc c-blosc2 before 3.5.0 divides by zero when reading a slice of a crafted Blosc2 frame that has a zero chunksize or blocksize. An attacker who supplies such a frame crashes the process that reads it (SIGFPE).","severity":"medium","cvss":6.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["blosc2","c-blosc2","package","python"],"not_affected_if":["trusted-input-only","version-3.5.0-or-later"],"how_to_check":"- Check the installed c-blosc2 version, for example `blosc2_version` or the package manager listing, and see whether it is below `3.5.0`.\n- Look for code that calls `blosc2_schunk_open()` or `blosc2_schunk_from_buffer()` on data from outside your control.","fix":"- c-blosc2 `3.5.0` (fixed version per the NVD description; the patch is linked from the sources)","status":"open","published_at":"2026-11-05T16:17:46+00:00","first_seen_at":"2026-11-05T16:40:02+00:00","triaged_at":"2026-11-05T16:41:40+00:00","updated_at":"2026-11-05T16:41:40+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-05T16:41:40Z","model":"claude-haiku-5-5","output":{"fix":"- c-blosc2 `3.5.0` (fixed version per the NVD description; the patch is linked from the sources)","reach":"unknown","title":"Blosc c-blosc2: crafted frame crashes applications via divide-by-zero","impact":"low","summary":"Blosc c-blosc2 before 3.5.0 divides by zero when reading a slice of a crafted Blosc2 frame that has a zero chunksize or blocksize. An attacker who supplies such a frame crashes the process that reads it (SIGFPE).","audience":"developers","category":"package","nicknames":[],"who_cares":["c-blosc2","python","blosc2"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"Process crashes on a crafted frame; denial of service only.","analyst_note":"","how_to_check":"- Check the installed c-blosc2 version, for example `blosc2_version` or the package manager listing, and see whether it is below `3.5.0`.\n- Look for code that calls `blosc2_schunk_open()` or `blosc2_schunk_from_buffer()` on data from outside your control.","plain_action":"","needs_analyst":false,"not_affected_if":["trusted-input-only","version-3.5.0-or-later"],"who_is_affected":"Applications that link c-blosc2 before 3.5.0 and open Blosc2 frames supplied from untrusted sources, such as uploaded or downloaded data files, can be crashed by a malicious frame. Programs that only read frames they created themselves, or that run in a trusted pipeline, are unlikely to be exposed. The sources do not say which downstream packages bundle c-blosc2.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.00074,"input_tokens":4349,"output_tokens":610,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-122330':16A,19A '-2026':15A,18A '3.5.0':31B,70C 'allow':87C 'applic':8A,91C 'attack':52B,88C,103C 'blocksiz':50B,101C 'blosc':1A,26B,65C 'blosc/schunk.c':85C 'blosc2':4A,20B,23B,29B,42B,68C,79C,108C,112C,116C 'buffer':83C,119C 'c':3A,22B,28B,67C 'c-blosc2':2A,21B,27B,66C 'chunksiz':48B,99C 'contain':71C 'craft':5A,41B,94C 'crash':7A,58B,90C 'cve':14A,17A 'divid':11A,32B,74C 'divide-by-zero':10A,73C 'frame':6A,43B,57B,95C,109C 'get':81C 'malici':107C 'open':110C,114C 'packag':24B 'process':60B,130C 'provid':105C 'python':25B 'rais':125C 'read':36B,62B,121C 'schunk':80C,113C,117C 'sigfp':64B,126C 'slice':38B,82C,124C 'suppli':54B,93C 'termin':128C 'uncheck':97C 'valu':102C 'via':9A,111C 'vulner':77C 'zero':13A,34B,47B,76C,98C","nicknames":[],"mitigations":[],"who_affected":"Applications that link c-blosc2 before 3.5.0 and open Blosc2 frames supplied from untrusted sources, such as uploaded or downloaded data files, can be crashed by a malicious frame. Programs that only read frames they created themselves, or that run in a trusted pipeline, are unlikely to be exposed. The sources do not say which downstream packages bundle c-blosc2.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["blosc2","cblosc2","medium","package","python"],"campaign_type":null,"first_public_at":"2026-11-05T16:17:46+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:X/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":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-122330","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-122330","severity":null,"published_at":"2026-11-05T16:17:46+00:00","modified_at":"2026-11-05T16:17:46+00:00","first_seen_at":"2026-11-05T16:40:02+00:00","fetched_at":"2026-11-05T16:40:02+00:00","note":null}],"documents":[{"id":77636,"url":"https://github.com/Blosc/c-blosc2/commit/4fff1787408d94b895c6f9cb50f7925ad5919052","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":77637,"url":"https://www.vulncheck.com/advisories/blosc-c-blosc2-before-3.5.0-divide-by-zero-via-blosc2-schunk-get-slice-buffer","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}