CVE-2026-68523 — Fulgur: Unbounded page slicing from attacker-controlled CSS height causes denial of service

Affected: fulgur-rs fulgur

`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. This is 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. As a workaround, validate or constrain untrusted CSS (in particular `height` / `vh` on body-level elements) before passing HTML to fulgur.

GHSA-j5cx-ph8g-95v3 — Fulgur: Unbounded page slicing from attacker-controlled CSS height causes denial of service

Affected: crates.io: fulgur

The height is taken directly from attacker-controlled HTML/CSS (`height`, `vh` units), so a few bytes such as:

```html <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.

## Patches

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.

## Workarounds

Upgrade to 0.19.0 or later. If upgrading is not immediately possible, validate or constrain untrusted CSS (in particular `height` / `vh` on body-level elements) before passing HTML to fulgur.

## Attack Vector rationale

`fulgur` performs no network I/O of its own; it renders HTML/CSS handed to it by the embedd…

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CVE-2026-68523 — Fulgur: Unbounded page slicing from attacker-controlled CSS height causes denial of service

GHSA-j5cx-ph8g-95v3 — Fulgur: Unbounded page slicing from attacker-controlled CSS height causes denial of service