# CVE-2026-68538: fulgur unbounded CSS counters expansion in generated content

Source: https://junglewise.ai/threats/cve-2026-68538-fulgur-converts-untrusted-html-css-into-pdf-commonly-on-a-server  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-11. Updated: 2026-11-11  
License: CC BY 4.0 with a link back

CVE-2026-68538 · Severity: high · CVSS 7.5 · Published 2026-11-11

fulgur is a library that converts HTML and CSS into PDF documents, often used by services that process user-supplied input from multiple customers. An attacker can submit specially crafted HTML/CSS to a fulgur-based conversion service to cause the server to exhaust CPU and memory resources, resulting in a denial of service that impacts the service and all co-hosted customers.

Technologies: [Fulgur-Rs Fulgur](https://junglewise.ai/threats/technologies/fulgur-rs-fulgur). Vendors: [Fulgur-Rs](https://junglewise.ai/threats/vendors/fulgur-rs).

## Quick answers

**Is CVE-2026-68538 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-68538 being exploited in the wild.

**How severe is CVE-2026-68538?** High severity, with a CVSS score of 7.5, published 11 November 2026.

**Which products and versions are affected?** Fulgur-Rs Fulgur 0.15.0 to before 0.27.0.

**Is there a fix for CVE-2026-68538?** Yes: fixed in 0.27.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-68538 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-68538?** Check whether you run Fulgur-Rs Fulgur at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 0.27.0

## Technical details

The vulnerability exists in fulgur's handling of the CSS counters(name, sep) function in generated content. The expansion of these counters was neither bounded in size for a single expansion nor in aggregate work across an element tree, allowing an attacker to trigger unbounded resource consumption. An attacker with the ability to submit HTML/CSS to a fulgur conversion service can trigger CPU and memory exhaustion with a trivial payload, and the fix applies resource limits to counter expansion.

## Affected products

- fulgur-rs fulgur 0.15.0 to before 0.27.0

## Timeline

- 2026-11-11: disclosed
- 2026-07-04: patched

## References

- [https://github.com/fulgur-rs/fulgur/commit/ebc75691ad368f1c1a211543313b04da2af466d6](https://github.com/fulgur-rs/fulgur/commit/ebc75691ad368f1c1a211543313b04da2af466d6)
- [https://github.com/fulgur-rs/fulgur/releases/tag/v0.27.0](https://github.com/fulgur-rs/fulgur/releases/tag/v0.27.0)

## Related threats

- [fulgur denial of service in absolutely-positioned pseudo-element layout](https://junglewise.ai/threats/cve-2026-68540-fulgur-converts-untrusted-html-css-into-pdf-commonly-on-a-server)
- [fulgur denial of service via unbudgeted CSS named-string values](https://junglewise.ai/threats/cve-2026-68539-fulgur-converts-untrusted-html-css-into-pdf-commonly-on-a-server)