zlib's untgz demonstration overruns a global buffer
zlib versions up to and including 1.3.1.2 include a global buffer overflow in the untgz utility located under contrib/untgz.
- Advisory
- CVE-2026-22184
- Library
- zlib, zlib on Debian
- Published
- Severity
- 7.8 out of 10, as published
- Affected
- zlib up to 1.3.1.2 (contrib/untgz only)
- Fixed in
- see the upstream record
- Reaches you
- through a command-line tool
What triggers it
Running the contrib/untgz demonstration utility with an over-long archive name.
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.
A standalone demonstration under contrib/, which the zlib library does not contain; no library call 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 zlib 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-2026-22184
- The record entry, triaged 2026-11-03, last checked 2026-11-03