NULL pointer dereference in Artifex Mupdf
CVE-2025-55780
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (36.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- bugs.ghostscript.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
- github.com/ISH2YU/CVE-2025-55780/tree/main (Third Party Advisory)
- cgit.ghostscript.com/cgi-bin/cgit.cgi/mupdf.git/commit/ (Permissions Required)
Frequently asked questions
- What is CVE-2025-55780?
- CVE-2025-55780 is a high-severity vulnerability in Artifex Mupdf, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2025-09-23.
- How severe is CVE-2025-55780?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2025-55780 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.