Vulnerability · Published Sep 23, 2025 · Assigned by mitre
CVE-2025-55780
High 7.5
In plain English
A high-severity null pointer dereference in the mupdf package (Debian). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
A null pointer dereference occurs in the function break_word_for_overflow_wrap() in MuPDF 1.26.4 when rendering a malformed EPUB document. Specifically, the function calls fz_html_split_flow() to split a FLOW_WORD node, but does not check if node->next is valid before accessing node->next->overflow_wrap, resulting in a crash if the split fails or returns a partial node chain.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | mupdf | no fix listed | DEBIAN-CVE-2025-55780 |
| Debian:13 | mupdf | no fix listed | DEBIAN-CVE-2025-55780 |
| Debian:14 | mupdf | 1.27.0+ds1-2 | DEBIAN-CVE-2025-55780 |
| Ubuntu:25.10 | mupdf | no fix listed | UBUNTU-CVE-2025-55780 |
| Ubuntu:26.04:LTS | mupdf | no fix listed | UBUNTU-CVE-2025-55780 |
| Ubuntu:26.10 | mupdf | no fix listed | UBUNTU-CVE-2025-55780 |
Affected products (as reported)
Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H