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Security · OpenJPEG

opj_decompress overruns a heap buffer with certain options (second report)

A flaw was found in the OpenJPEG project.

Advisory
CVE-2024-56827
Library
OpenJPEG, openjpeg2 on Debian
Published
Severity
5.6 out of 10, as published
Affected
OpenJPEG, as packaged; see the upstream record
Fixed in
see the upstream record
Reaches you
through a command-line tool

What triggers it

Running the opj_decompress command-line tool with particular options on a crafted JPEG 2000 file.

What sillybos does

Not reached by opening a file

Opening or reading a file never reaches this flaw, so a check before decoding has nothing to refuse. Listed so that nobody expects it to.

As CVE-2024-56826: the opj_decompress utility, not a library call opening a file; a JPEG 2000 file is refused by name in any case.

Proposed from the advisory's text on 2026-11-01, as part of folding the backfill into the record; confirmed by a person on 2026-11-03.

How to protect yourself

In general. Upgrade OpenJPEG to a version that has the fix; the upstream record names it.

Specifically. Not a pre-decode matter: a command-line tool, not the library, runs the flawed code.

The general advice applies to every row here.

Sources