Fulgur: Unbounded page slicing from attacker-controlled CSS height causes denial of service

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-68523: 0.61% estimated exploitation activity in the next 30 days; percentile 49.22 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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: forced on the order of 125,000 page fragments. The pagination code then allocates vec![Vec::new(); pagecount] 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 -= lastsliceh 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 MAXPAGES cap bounds the slice loop — halting it even for a +inf height…

Published by the source

17 Sep 2026, 18:48 UTC

Last modified by the source

17 Sep 2026, 19:10 UTC

Source last checked

26 Oct 2026, 15:43 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-j5cx-ph8g-95v3

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-j5cx-ph8g-95v3

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# Patch Next advisory brief: CVE-2026-68523

Advisory: Fulgur: Unbounded page slicing from attacker-controlled CSS height causes denial of service
IDs: CVE-2026-68523, GHSA-j5cx-ph8g-95v3
Record: https://patchnext.com/advisories/cve-2026-68523 (revision 2, source checked 26 Oct 2026, 15:43 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: fulgur 0.19.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io fulgur: affected < 0.19.0; fixed in 0.19.0

## Suggested inspection (read-only)
- crates.io fulgur: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on fulgur.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-j5cx-ph8g-95v3 (OSV record GHSA-j5cx-ph8g-95v3 lists affected ranges: crates.io fulgur >=0 <0.19.0 (fixed))
- Verified: https://github.com/advisories/GHSA-j5cx-ph8g-95v3 (GitHub-reviewed advisory GHSA-j5cx-ph8g-95v3 lists affected ranges: crates.io fulgur >=0 <0.19.0)

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