Varnish vulnerabilities and fixes

CVEs that mention Varnish, ranked by priority. 4 tracked.

Varnish has 4 tracked vulnerabilities, 0 critical. A fixed release or vendor patch exists for 3. Most recent: 2026-04-12. Highest priority: CVE-2026-34475 (score 27/100).

• CVE-2026-34475 MEDIUM 5.4 UPGRADE UPGRADE Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mi
• CVE-2026-40396 MEDIUM 4.0 DOWNGRADE Varnish Cache 9 before 9.0.1 allows a "workspace overflow" denial of service (daemon panic) after timeout_ling
• CVE-2026-40394 MEDIUM 4.0 UPGRADE DOWNGRADE Varnish Cache 9 before 9.0.1 and Varnish Enterprise before 6.0.16r11 allows a "workspace overflow" denial of s
• CVE-2026-40395 MEDIUM 4.0 UPGRADE Varnish Enterprise before 6.0.16r12 allows a "workspace overflow" denial of service (daemon panic) for shared

FAQ

How do I fix Varnish 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 Varnish being exploited right now?

None of the tracked Varnish CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.

Which Varnish CVE should I patch first?

CVE-2026-34475 currently ranks highest (27/100): Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mi.

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