CVE-2026-4176
Perl versions from 5.9.4 before 5.40.4-RC1, from 5.41.0 before 5.42.2-RC1, from 5.43.0 before 5.43.9 contain a vulnerable version of Compress::Raw::Zlib. Compress::Raw::Zlib is included in the Perl package as a dual-life core module, and is vulnerable to CVE-2026-3381 due to a vendored version of zlib which has several vulnerabilities, including CVE-2026-27171. The bundled Compress::Raw::Zlib was updated to version 2.221 in Perl blead commit c75ae9cc164205e1b6d6dbd57bd2c65c8593fe94.
- Affected products
- Compress::Raw::Zlib, Perl, Red Os
- Perl
- < 5.40.4, 5.42.2, 5.43.9
- Fix
- Available
- CVSS 3.1
- 9.8 CRITICAL
- EPSS
- 0.7% (49th percentile)
- Weakness
- CWE-1395
- NVD status
- Analyzed
- Published
- 2026-03-29
Fix
Update to Perl stable release 5.40.4 or 5.42.2 or later, which include Compress::Raw::Zlib 2.222.
Workaround
Install Compress::Raw::Zlib 2.220 or later into your @INC include path, so it takes precedence over the vulnerable core module shipped with Perl. Some OS distributions patch their perl package to build Compress::Raw::Zlib against the system zlib rather than the vendored copy. Users of these distributions may not be affected if their system zlib has been updated to 1.3.2 or later, or includes backported patches for the relevant vulnerabilities.
No indexed exploits for CVE-2026-4176 yet
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No exploit for CVE-2026-4176 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.