{"id":"GHSA-6fj4-rcr3-r7rr","summary":"lopdf has a stack overflow via deeply nested PDF objects","details":"`lopdf::Document::load_mem` (and the other `load*` entry points) parses nested PDF arrays and dictionaries with unbounded recursion. A small crafted PDF whose Catalog contains a deeply nested array (`/X [[[ … ]]]`, on the order of 10,000 levels) exhausts the call stack and aborts the process with `SIGABRT`.\n\nBecause this is a stack-overflow abort rather than a `panic!`, it cannot be caught with `catch_unwind`: any service that parses untrusted PDF input with lopdf can be crashed by a ~21 KB file, resulting in a denial of service.\n\nConfirmed on lopdf 0.41.0 and earlier; fixed in 0.42.0. Default configuration, no features changed.\n\n## Proof of concept\n\n```rust\nfn main() {\n    let bytes = std::fs::read(\"poc.pdf\").unwrap(); // ~10,380-deep nested array in the Catalog\n    let _ = lopdf::Document::load_mem(&bytes);     // stack overflow -\u003e SIGABRT\n}\n```\n\nAn equivalent PoC is a minimal PDF whose Catalog `/X` value is `\"[\" * 10380 + \"]\" * 10380`.\n\n## Suggested fix\n\nEnforce a maximum object-nesting depth in the parser and return an `Err` instead of recursing without bound.","modified":"2026-10-16T20:00:04.075387442Z","published":"2026-10-16T19:55:39Z","database_specific":{"cwe_ids":["CWE-1124"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-10-16T19:55:39Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/J-F-Liu/lopdf/issues/502"},{"type":"WEB","url":"https://github.com/J-F-Liu/lopdf/pull/503"},{"type":"WEB","url":"https://github.com/J-F-Liu/lopdf/commit/c755394ad7dd651ccfe77c618f90ab779da1dfd9"},{"type":"PACKAGE","url":"https://github.com/J-F-Liu/lopdf"},{"type":"WEB","url":"https://rustsec.org/advisories/RUSTSEC-2026-0187.html"}],"affected":[{"package":{"name":"lopdf","ecosystem":"crates.io","purl":"pkg:cargo/lopdf"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.42.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-6fj4-rcr3-r7rr/GHSA-6fj4-rcr3-r7rr.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}