CVE-2025-71382
MEDIUMMuPDF 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…
Description
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.
Affected Products
mupdfartifexDetection & mitigation playbook
Vendor / applianceDetect
Inventory every artifex mupdf deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the artifex mupdf security patch or hotfix for CVE-2025-71382 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2025-71382 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2025-71382. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-71382 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2025-71382 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.