Heap-based buffer overflow in Calibre - #VU146755
Published: September 2, 2026
Vulnerability identifier: #VU146755
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to a heap-based buffer overflow in cpalmdoc_compress() when processing crafted book content during document conversion. A remote user can supply a specially crafted document or trigger conversion of a crafted book to cause a denial of service.
PalmDoc compression is the default for MOBI and AZW3 output and unconditional for PDB. A write-authenticated content server conversion path is also affected.
Affected software
Calibre
Remediation
Install security update from vendor's website.
Calibre - update to 9.13.0