{"id":"RUSTSEC-2026-0187","aliases":["GHSA-6fj4-rcr3-r7rr"],"title":"Stack overflow in lopdf via deeply nested PDF objects","summary":"Stack overflow in lopdf via deeply nested PDF objects","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"lopdf","product":"lopdf","ecosystem":"rust","affected":["lopdf >= 0.0.0-0, < 0.42.0"],"patched":["lopdf 0.42.0"],"published":"2026-06-21","updated":"2026-10-17","sourceUpdated":"2026-10-17T15:15:02.582897646Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/RUSTSEC-2026-0187","references":[{"url":"https://crates.io/crates/lopdf"},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0187.html"},{"url":"https://github.com/J-F-Liu/lopdf/issues/502"},{"url":"https://github.com/J-F-Liu/lopdf/pull/503"},{"url":"https://github.com/J-F-Liu/lopdf/commit/c755394"}],"tags":["osv","rust"],"ingestedAt":"2026-10-18T11:51:09.858Z","slug":"RUSTSEC-2026-0187","body":"## Overview\n\n`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 -> 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.\n\n## Affected packages\n\n- `lopdf >= 0.0.0-0, < 0.42.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `lopdf 0.42.0`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}