CVE-2025-55780
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductArtifex Mupdf
PublishedSep 23, 2025
First seenSep 23, 2025
Weakness typeCWE-476NULL pointer dereference
How to fix
Update
- artifex mupdf1.26.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| artifex mupdf | 1.24.0 ≤ v < 1.26.7 | 1.26.7 |
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