{"id":"CVE-2026-115580","kind":"vulnerability","aliases":["CVE-2026-115580","GHSA-gmh7-3g9r-mjh5"],"related":[],"title":"pypdf: Possible long runtimes for large xref table header limits","description":"### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires opening a file with large/wrong upper limits in the xref table.\n\n### Patches\n\nThis has been fixed in [pypdf==6.21.2](https://github.com/py-pdf/pypdf/releases/tag/6.21.2).\n\n### Workarounds\n\nIf you cannot upgrade yet, consider applying the changes from PR [#4239](https://github.com/py-pdf/pypdf/pull/4239).","summary":"pypdf, a Python PDF library, can be made to run for a very long time when it opens a crafted PDF with a large or wrong upper limit in the xref table. An attacker who can get the application to parse such a file can tie up CPU and stall the process (denial of service).","severity":"high","cvss":7.1,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"pypdf","fixed":["6.21.2"],"affected":"< 6.21.2","ecosystem":"pypi"}],"ecosystems":["pypi"],"tags":["cwe-834","document-processing","package","pypdf","python","self-hosted"],"not_affected_if":["no-untrusted-pdf-input","pypdf-below-6.21.2-not-installed"],"how_to_check":"Run: pip show pypdf (or pip freeze | grep -i pypdf) and confirm the version is 6.21.2 or newer.\nSearch the lockfiles and requirements for pypdf to find every place it is pinned.","fix":"Upgrade pypdf to 6.21.2 or newer: pip install --upgrade 'pypdf>=6.21.2'.\nIf you cannot upgrade yet, apply the changes from PR #4239 (https://github.com/py-pdf/pypdf/pull/4239).","status":"open","published_at":"2026-10-23T20:17:21+00:00","first_seen_at":"2026-10-23T20:59:05+00:00","triaged_at":"2026-10-23T21:00:31+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-23T21:00:31Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade pypdf to 6.21.2 or newer: pip install --upgrade 'pypdf>=6.21.2'.\nIf you cannot upgrade yet, apply the changes from PR #4239 (https://github.com/py-pdf/pypdf/pull/4239).","reach":"unknown","impact":"low","summary":"pypdf, a Python PDF library, can be made to run for a very long time when it opens a crafted PDF with a large or wrong upper limit in the xref table. An attacker who can get the application to parse such a file can tie up CPU and stall the process (denial of service).","category":"package","who_cares":["python","pypdf","document-processing","self-hosted"],"confidence":0.7,"needs_auth":"unknown","worst_case":"Parsing a crafted PDF stalls the process for a long time (denial of service).","analyst_note":"","how_to_check":"Run: pip show pypdf (or pip freeze | grep -i pypdf) and confirm the version is 6.21.2 or newer.\nSearch the lockfiles and requirements for pypdf to find every place it is pinned.\nunknown","needs_analyst":false,"not_affected_if":["pypdf-below-6.21.2-not-installed","no-untrusted-pdf-input"],"user_interaction":"unknown","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000525,"input_tokens":2887,"output_tokens":472,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-115580':13A,21A '-2026':12A,20A '-834':24B '/py-pdf/pypdf/pull/4239).':144C '/py-pdf/pypdf/releases/tag/6.21.2).':128C '3g9r':17A '4239':141C '6.21.2':125C 'appli':136C 'applic':72B 'attack':67B,91C 'cannot':132C 'chang':138C 'consid':135C 'cpu':81B 'craft':53B,97C 'cve':11A,19A 'cwe':23B 'denial':86B 'document':26B 'document-process':25B 'file':77B,109C 'fix':122C 'get':70B 'ghsa':15A 'ghsa-gmh7-3g9r-mjh5':14A 'github.com':127C,143C 'github.com/py-pdf/pypdf/pull/4239).':142C 'github.com/py-pdf/pypdf/releases/tag/6.21.2).':126C 'gmh7':16A 'header':9A 'host':33B 'impact':89C 'larg':6A,57B 'large/wrong':111C 'lead':101C 'librari':38B 'limit':10A,61B,113C 'long':3A,47B,103C 'made':41B 'mjh5':18A 'open':51B,107C 'packag':28B 'pars':74B 'patch':118C 'pdf':37B,54B,99C 'possibl':2A 'pr':140C 'process':27B,85B 'pypdf':1A,22A,29B,34B,124C 'python':30B,36B 'requir':106C 'run':43B 'runtim':4A,104C 'self':32B 'self-host':31B 'servic':88B 'stall':83B 'tabl':8A,65B,117C 'tie':79B 'time':48B 'upgrad':133C 'upper':60B,112C 'use':93C 'vulner':95C 'workaround':129C 'wrong':59B 'xref':7A,64B,116C 'yet':134C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T20:17:21+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/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":"security-advisories@github.com","poc_count":0,"sources":[{"source":"ghsa","external_id":"GHSA-gmh7-3g9r-mjh5","url":"https://github.com/advisories/GHSA-gmh7-3g9r-mjh5","severity":"high","published_at":"2026-10-23T20:54:12+00:00","modified_at":"2026-10-23T20:54:14+00:00","first_seen_at":"2026-10-23T20:59:05+00:00","fetched_at":"2026-10-23T20:59:05+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-115580","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115580","severity":null,"published_at":"2026-10-23T20:17:21+00:00","modified_at":"2026-10-23T20:17:21+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","fetched_at":"2026-10-23T22:29:04+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"}