{"id":"CVE-2026-113793","kind":"vulnerability","aliases":["CVE-2026-113793","GHSA-9mx8-4j7g-633p"],"related":[],"title":"pypdf: Possible infinite loop when removing tree items","description":"### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires removing an object from a tree, for example an outline item.\n\n### Patches\n\nThis has been fixed in [pypdf==6.20.1](https://github.com/py-pdf/pypdf/releases/tag/6.20.1).\n\n### Workarounds\n\nIf you cannot upgrade yet, consider applying the changes from PR [#4188](https://github.com/py-pdf/pypdf/pull/4188).","summary":"pypdf, a Python PDF library, can enter an infinite loop when it removes an object from a PDF tree such as an outline item in a crafted file. An attacker who supplies such a PDF can hang the process that parses it, causing a denial of service.","severity":"medium","cvss":6.0,"epss":0.004660000093281269,"exploited":false,"exploited_at":null,"products":[{"name":"pypdf","fixed":["6.20.1"],"affected":"< 6.20.1","ecosystem":"pypi"}],"ecosystems":["pypi"],"tags":["cwe-835","document-processing","package","pypdf","python"],"not_affected_if":["does-not-remove-tree-items","no-untrusted-pdfs"],"how_to_check":"Run pip show pypdf and check whether the version is below 6.20.1.\nSearch requirements or lock files for pypdf to find pinned versions.","fix":"Upgrade pypdf to 6.20.1 or later.\nIf you cannot upgrade yet, apply the changes from PR #4188 in the pypdf repository as the advisory suggests.","status":"open","published_at":"2026-10-21T16:17:27+00:00","first_seen_at":"2026-10-23T19:11:32+00:00","triaged_at":"2026-10-23T20:10:23+00:00","updated_at":"2026-10-23T21:57:29+00:00","category":"package","confidence":0.85,"triage":{"at":"2026-10-23T20:10:23Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade pypdf to 6.20.1 or later.\nIf you cannot upgrade yet, apply the changes from PR #4188 in the pypdf repository as the advisory suggests.","summary":"pypdf, a Python PDF library, can enter an infinite loop when it removes an object from a PDF tree such as an outline item in a crafted file. An attacker who supplies such a PDF can hang the process that parses it, causing a denial of service.","category":"package","who_cares":["python","pypdf","document-processing"],"confidence":0.85,"analyst_note":"","how_to_check":"Run pip show pypdf and check whether the version is below 6.20.1.\nSearch requirements or lock files for pypdf to find pinned versions.\nunknown","needs_analyst":false,"not_affected_if":["does-not-remove-tree-items","no-untrusted-pdfs"],"severity_if_unknown":"medium"},"cost_usd":0.00037,"input_tokens":2114,"output_tokens":318,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-113793':11A,19A '-2026':10A,18A '-835':22B '/py-pdf/pypdf/pull/4188).':132C '/py-pdf/pypdf/releases/tag/6.20.1).':116C '4188':129C '4j7g':15A '6.20.1':113C '633p':16A '9mx8':14A 'appli':124C 'attack':58B,78C 'cannot':120C 'caus':71B 'chang':126C 'consid':123C 'craft':55B,84C 'cve':9A,17A 'cwe':21B 'denial':73B 'document':24B 'document-process':23B 'enter':35B 'exampl':102C 'file':56B 'fix':110C 'ghsa':13A 'ghsa-9mx8-4j7g-633p':12A 'github.com':115C,131C 'github.com/py-pdf/pypdf/pull/4188).':130C 'github.com/py-pdf/pypdf/releases/tag/6.20.1).':114C 'hang':65B 'impact':76C 'infinit':3A,37B,91C 'item':8A,52B,105C 'lead':88C 'librari':33B 'loop':4A,38B,92C 'object':43B,97C 'outlin':51B,104C 'packag':26B 'pars':69B 'patch':106C 'pdf':32B,46B,63B,86C 'possibl':2A 'pr':128C 'process':25B,67B 'pypdf':1A,20A,27B,29B,112C 'python':28B,31B 'remov':6A,41B,95C 'requir':94C 'servic':75B 'suppli':60B 'tree':7A,47B,100C 'upgrad':121C 'use':80C 'vulner':82C 'workaround':117C 'yet':122C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-21T16:17:27+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/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-9mx8-4j7g-633p","url":"https://github.com/advisories/GHSA-9mx8-4j7g-633p","severity":"medium","published_at":"2026-10-21T16:55:10+00:00","modified_at":"2026-10-21T16:55:12+00:00","first_seen_at":"2026-10-23T19:11:32+00:00","fetched_at":"2026-10-23T19:11:32+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-113793","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-113793","severity":null,"published_at":"2026-10-21T16:17:27+00:00","modified_at":"2026-10-22T16:46:48+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","fetched_at":"2026-10-23T22:29:01+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"}