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RUSTSEC-2026-0187
No affected components available
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.
Because 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.
Confirmed on lopdf 0.41.0 and earlier; fixed in 0.42.0. Default configuration, no features changed.
Proof of concept
fn main() {
let bytes = std::fs::read("poc.pdf").unwrap(); // ~10,380-deep nested array in the Catalog
let _ = lopdf::Document::load_mem(&bytes); // stack overflow -> SIGABRT
}
An equivalent PoC is a minimal PDF whose Catalog /X value is "[" * 10380 + "]" * 10380.
Suggested fix
Enforce a maximum object-nesting depth in the parser and return an Err instead of recursing without bound.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the availability of the system.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
Probability that this vulnerability will be exploited in the wild within the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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