tiff2pdf truncates a BigTIFF strip byte count and overflows
A flaw was found in libtiff.
- Advisory
- CVE-2026-18495
- Library
- libtiff, tiff on Debian
- Published
- Severity
- 6.1 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 the tiff2pdf command-line tool on a crafted BigTIFF.
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 the tiff2pdf utility, and through a BigTIFF, which sillybos refuses by name in any case; 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-2026-18495
- The record entry, triaged 2026-11-03, last checked 2026-11-03