PatchTheCVEzlib vulnerabilities and fixes
Recent CVEs affecting zlib, with upgrade or downgrade steps. 1 tracked.
zlib has 1 tracked vulnerability, 1 critical. A fixed release or vendor patch exists for 1. Most recent: 2026-04-16. Highest priority: CVE-2026-27820 (score 51/100).
- CVE-2026-27820 CRITICAL 9.8 UPGRADE zlib is a Ruby interface for the zlib compression/decompression library
FAQ
How do I fix zlib vulnerabilities?
Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.
Is zlib being exploited right now?
None of the tracked zlib CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.
Which zlib CVE should I patch first?
CVE-2026-27820 currently ranks highest (51/100): zlib is a Ruby interface for the zlib compression/decompression library.