MuPDF before 1.27.0-rc1 contains an uncontrolled recursion vulnerability in the EPUB CSS rendering engine that allows remote attackers to cause a denial of service by supplying a maliciously crafted EPUB file with deeply nested HTML elements and inline CSS styles. The function value_from_inheritable_property() in css-apply.c recurses through the CSS property inheritance chain without a depth limit, exhausting the process stack and causing a crash in any application using MuPDF for EPUB rendering.
https://www.vulncheck.com/advisories/mupdf-rc1-stack-exhaustion-dos-via-epub-css-rendering
https://github.com/ArtifexSoftware/mupdf/releases/tag/1.27.0-rc1
https://github.com/ArtifexSoftware/mupdf/commit/70b71ab22e6de4d4c44cd301c88231f623a4e94e
Published: 2026-06-23
Updated: 2026-06-23
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C
Severity: High
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 7.1
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High