{"id":"CVE-2026-9535","kind":"vulnerability","aliases":["CVE-2026-9535"],"related":[],"title":"VTK: crafted Chaco file triggers out-of-bounds read in reader","description":"A out-of-bounds read vulnerability exists in the vtkChacoReader InputGraph2 functionality of vtk (version(s): 9.6.1). A specially crafted chaco can lead to an out-of-bounds read. An attacker can provide a malicious file to trigger this vulnerability.","summary":"The Visualization Toolkit (VTK) 9.6.1 has an out-of-bounds read in its vtkChacoReader InputGraph2 code path. A specially crafted Chaco graph file can make the reader read memory outside its buffer, and an attacker can exploit this by supplying a malicious file.","severity":"high","cvss":8.2,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"vtk","fixed":[],"affected":"9.6.1","ecosystem":"vendor"}],"ecosystems":[],"tags":["c++","package","scientific-computing","vtk"],"not_affected_if":["no-chaco-input","not-version-9.6.1","trusted-files-only"],"how_to_check":"- Check the installed VTK version, for example `vtkVersion` in your build or the package manager listing, and look for `9.6.1`.\n- Search your code and pipelines for use of `vtkChacoReader` or InputGraph2 reading untrusted Chaco files.","fix":null,"status":"open","published_at":"2026-10-29T19:17:29+00:00","first_seen_at":"2026-10-29T19:26:48+00:00","triaged_at":"2026-10-29T19:27:16+00:00","updated_at":"2026-10-29T19:28:23+00:00","category":"package","confidence":0.5,"triage":{"at":"2026-10-29T19:27:16Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"VTK: crafted Chaco file triggers out-of-bounds read in reader","impact":"low","summary":"The Visualization Toolkit (VTK) 9.6.1 has an out-of-bounds read in its vtkChacoReader InputGraph2 code path. A specially crafted Chaco graph file can make the reader read memory outside its buffer, and an attacker can exploit this by supplying a malicious file.","audience":"developers","category":"package","nicknames":[],"who_cares":["vtk","c++","scientific-computing"],"confidence":0.5,"fix_status":"unknown","needs_auth":"no","worst_case":"Memory outside the buffer is read, possibly leaking data or crashing the process.","analyst_note":"Check the NVD entry and the VTK project for the fixed version and whether the Chaco reader is built by default; the sources give no fix or exploitation detail.","how_to_check":"- Check the installed VTK version, for example `vtkVersion` in your build or the package manager listing, and look for `9.6.1`.\n- Search your code and pipelines for use of `vtkChacoReader` or InputGraph2 reading untrusted Chaco files.","plain_action":"","needs_analyst":true,"not_affected_if":["not-version-9.6.1","no-chaco-input","trusted-files-only"],"who_is_affected":"Teams that build or run software on VTK 9.6.1 and pass it Chaco graph files from outside their control. Applications that never read Chaco files, or only read files they generated, are less exposed. The sources do not say whether a default build includes this reader.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000711,"input_tokens":4137,"output_tokens":594,"severity_before":"high"},"analyst_status":"done","analyst_note":"Check the NVD entry and the VTK project for the fixed version and whether the Chaco reader is built by default; the sources give no fix or exploitation detail.","search":"'-2026':14A,17A '-9535':15A,18A '9.6.1':30B,87C 'attack':61B,102C 'bound':9A,36B,74C,99C 'buffer':58B 'c':20B 'chaco':3A,47B,91C 'code':42B 'comput':24B 'craft':2A,46B,90C 'cve':13A,16A 'exist':77C 'exploit':63B 'file':4A,49B,69B,107C 'function':82C 'graph':48B 'inputgraph2':41B,81C 'lead':93C 'make':51B 'malici':68B,106C 'memori':55B 'out-of-bound':6A,33B,71C,96C 'outsid':56B 'packag':21B 'path':43B 'provid':104C 'read':10A,37B,54B,75C,100C 'reader':12A,53B 'scientif':23B 'scientific-comput':22B 'special':45B,89C 'suppli':66B 'toolkit':28B 'trigger':5A,109C 'version':85C 'visual':27B 'vtk':1A,19A,25B,29B,84C 'vtkchacoread':40B,80C 'vulner':76C,111C","nicknames":[],"mitigations":[],"who_affected":"Teams that build or run software on VTK 9.6.1 and pass it Chaco graph files from outside their control. Applications that never read Chaco files, or only read files they generated, are less exposed. The sources do not say whether a default build includes this reader.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"developers","plain_action":null,"first_public_at":"2026-10-29T19:17:29+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","cvss_by":"talos-cna@cisco.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-9535","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9535","severity":null,"published_at":"2026-10-29T19:17:29+00:00","modified_at":"2026-10-29T19:17:29+00:00","first_seen_at":"2026-10-29T19:26:48+00:00","fetched_at":"2026-10-29T19:26:48+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-9535:1098","url":null,"severity":null,"published_at":"2026-10-29T19:28:23+00:00","modified_at":"2026-10-29T19:28:23+00:00","first_seen_at":"2026-10-29T19:28:23+00:00","fetched_at":"2026-10-29T19:28:23+00:00","note":"No Talos/VTK advisory found yet; only NVD (Talos CNA) text. vtkChacoReader::InputGraph2 exists in VTK 9.6 docs (linked). VTK 9.6.2 was released 2026-05-18 but no source says it fixes this; fix unknown. Not exploited, no PoC found. Settle by reading the Talos report or the VTK GitLab issue."}],"documents":[{"id":18900,"url":"https://vtk.org/doc/nightly/release/9.6/html/classvtkChacoReader.html","title":"VTK: vtkChacoReader Class Reference (9.6)","kind":"other","source":"analyst","publisher":null,"text":null,"published_at":null,"relation":"describes","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}