CVE-2026-25556: MuPDF 1.23.0 through 1.27.0 Barcode Decoding Double Free
MuPDF versions 1.23.0 through 1.27.0 contain a double-free vulnerability in fzfillpixmapfromdisplaylist() when an exception occurs during display list rendering. The function accepts a caller-owned fzpixmap pointer but incorrectly drops the pixmap in its error handling path before rethrowing the exception. Callers (including the barcode decoding path in fzdecodebarcodefromdisplaylist) also drop the same pixmap in cleanup, resulting in a double-free that can corrupt the heap and crash the process. This issue affects applications that enable and use MuPDF barcode decoding and can be triggered by processing crafted input that causes a rendering-time error while decoding barcodes.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-25556?
CVE-2026-25556 is classified as a medium severity vulnerability due to the potential for exploitation leading to application instability.
How do I fix CVE-2026-25556?
To address CVE-2026-25556, upgrade MuPDF to version 1.28.0 or later, where the double-free vulnerability has been resolved.
What versions of MuPDF are affected by CVE-2026-25556?
CVE-2026-25556 affects MuPDF versions from 1.23.0 up to 1.27.0 inclusively.
Can CVE-2026-25556 lead to a denial of service attack?
Yes, an attacker could potentially exploit CVE-2026-25556 to cause a denial of service by triggering the double-free condition.
Is CVE-2026-25556 a remote vulnerability?
CVE-2026-25556 can be exploited remotely if the affected software processes untrusted display lists.