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Findings

Security fix · RUSTSEC-2026-0187

Stack overflow in lopdf via deeply nested PDF objects

Published Jun 21, 2026 · corrected/updated Oct 17, 2026 · evidence confidence medium

(and the other entry points) parses nested PDF arrays and dictionaries with unbounded recursion. A small crafted PDF whose Catalog contains a deeply nested array ( , on the order of 10,000 levels) exhausts the call stack and aborts the process with . Because this is a stack-overflow abort rather than a , it cannot be caught with : any service that parses untrusted PDF input with lopdf can be crashed by a ~21 KB file, resulting in a denial of service. Confirmed on lopdf 0.41.0 and earlier; fixed in 0.42.0. Default configuration, no features changed. ## Proof of concept An equivalent PoC is a minimal PDF whose Catalog value is . ## Suggested fix Enforce a maximum object-nesting depth in the parser and return an instead of recursing without bound.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

RUSTSEC-2026-0187 is a high public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: lopdf (0.0.0-0 → 0.42.0). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 7.5. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: github, osv. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 21, 2026 · GitHub Advisory Database

    Detected

    (and the other entry points) parses nested PDF arrays and dictionaries with unbounded recursion. A small crafted PDF whose Catalog contains a deeply nested array ( , on the order of 10,000 levels) exhausts the call stack and aborts the process with . Because this is a stack-overflow abort rather than a , it cannot be caught with : any service that parses untrusted PDF input with lopdf can be crash

  2. Oct 17, 2026 · GitHub Advisory Database

    Fix available

    lopdf fixed in 0.42.0

  3. Oct 17, 2026 · GitHub Advisory Database

    Fix available

    lopdf fixed in 0.42.0

  4. Oct 17, 2026 · GitHub Advisory Database

    Updated

    (and the other entry points) parses nested PDF arrays and dictionaries with unbounded recursion. A small crafted PDF whose Catalog contains a deeply nested array ( , on the order of 10,000 levels) exhausts the call stack and aborts the process with . Because this is a stack-overflow abort rather than a , it cannot be caught with : any service that parses untrusted PDF input with lopdf can be crash

Affected

  • crates.io lopdf0.0.0-0 → 0.42.0

Sources

References