The thumbnail tool's main allows arbitrary code execution
An issue in libtiff 85f2ac8e0b01cb7db2bbecf4a3b891bdbef67938 allows an attacker to execute arbitrary code via the libtiff/tools/thumbnail.c: main() component
- Advisory
- CVE-2026-52491
- Library
- libtiff, tiff on Debian
- Published
- Severity
- 8.4 out of 10, as published
- Affected
- libtiff, as packaged; see the upstream record
- Fixed in
- see the upstream record
- Reaches you
- through a command-line tool
What triggers it
Running LibTIFF's thumbnail command-line tool with crafted input.
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.
In tools/thumbnail.c, a command-line tool; no library call opening a file runs it.
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 libtiff 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
- https://osv.dev/vulnerability/DEBIAN-CVE-2026-52491
- The record entry, triaged 2026-11-03, last checked 2026-11-03