RUSTSEC-2026-0200: Unbounded page slicing from attacker-controlled CSS height causes denial of service

What to do

1. See which version you have: cargo tree -i fulgur (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p fulgur. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example fulgur = "0.19.0") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

fulgur converts untrusted HTML/CSS into PDF, commonly on a server that processes input supplied by many tenants. In versions prior to 0.19.0, a body-direct child whose CSS-resolved height greatly exceeds the page height was sliced into one fragment per page with no upper bound.

The height is taken directly from attacker-controlled HTML/CSS (height, vh units), so a few bytes such as <div style="height:99999999px"></div> forced on the order of 125,000 page fragments. The pagination code then allocates vec![Vec::new(); page_count] and runs a per-page render loop, resulting in CPU and memory exhaustion. A non-finite height (one that resolves to +inf) additionally made the slicing loop's remaining -= last_slice_h decrement never terminate, causing an infinite loop.

An attacker able to submit HTML/CSS to a fulgur-based conversion service can trigger this with a trivially small payload, denying service to the host and any co-tenants.

Fixed in 0.19.0: a MAX_PAGES cap bounds the slice loop , halting it even for a +inf height , and non-finite layout heights are sanitized so they can no longer drive the loop.

Attack Vector rationale

fulgur performs no network I/O of its own; it renders HTML/CSS handed to it by the embedding application. This advisory scores the crate independent of any specific adopting program, so per the CVSS v3.1 User Guide §3.7 the Attack Vector is assessed as Network for the reasonable worst-case deployment , a network-facing service that renders untrusted HTML without user interaction. A concrete system that receives the HTML in one component and passes it to fulgur in a separate component may assess a lower environmental Attack Vector (Local, per §3.10).

References

• Package: crates.io/crates/fulgur
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0200.html
• Web: github.com/fulgur-rs/fulgur/pull/501

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for fulgur

• Vulnerability HighRUSTSEC-2026-0201 · 2026-07-05Non-painting replaced elements amplify to thousands of blank PDF pages (denial of service)

Full security history of fulgur