CVE-2026-34475: Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mi

Q: How do I fix CVE-2026-34475?

varnish enterprise: upgrade to newer than 6.0.15; vinyl cache: upgrade to 8.0.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-34475 being exploited?

CVE-2026-34475 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-34475 affect?

CVE-2026-34475 affects varnish enterprise, vinyl cache. Severity is medium (CVSS 5.4). Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mishandle URLs with a path of / for HTTP/1.1, potentially leading to cache poisoning or authentication bypass.

Q: How urgent is CVE-2026-34475?

Priority 27/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.4REMOTEUPGRADEUPGRADE

CVE-2026-34475 is a medium-severity flaw (CVSS 5.4) affecting varnish enterprise, vinyl cache. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mishandle URLs with a path of / for HTTP/1.1, potentially leading to cache poisoning or authentication bypass.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 89%)
CISA exploited list	No
Weakness	CWE-180
Published	2026-03-27
Last modified	2026-10-26

Publisher (CNA): MITRE · Vendor: varnish-software · vinyl-cache

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-27 20:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

varnish-software varnish enterprise UPGRADE

Affected: <= 6.0.15 · 6.0.16 r1 · 6.0.16 r10 · 6.0.16 r11 · 6.0.16 r2 · 6.0.16 r3 · 6.0.16 r4 · 6.0.16 r5

Fixed in: newer than 6.0.15

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy varnish-enterprise || rpm -q varnish-enterprise || varnish-enterprise --version

2. UPGRADE to newer than 6.0.15 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade varnish-enterprise

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade varnish-enterprise

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

vinyl-cache vinyl cache UPGRADE

Affected: < 8.0.1

Fixed in: 8.0.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy vinyl-cache || rpm -q vinyl-cache || vinyl-cache --version

2. UPGRADE to 8.0.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade vinyl-cache

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade vinyl-cache

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34475?

varnish enterprise: upgrade to newer than 6.0.15; vinyl cache: upgrade to 8.0.1. Exact commands for each OS are on this page.

Is CVE-2026-34475 being exploited?

CVE-2026-34475 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34475 affect?

CVE-2026-34475 affects varnish enterprise, vinyl cache. Severity is medium (CVSS 5.4). Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mishandle URLs with a path of / for HTTP/1.1, potentially leading to cache poisoning or authentication bypass.

How urgent is CVE-2026-34475?

Priority 27/100. Remotely exploitable, no login, no user action

Software pages

Varnish vulnerabilities

Related CVEs

CVE-2026-40395 MEDIUM 4.0 UPGRADE Varnish Enterprise before 6.0.16r12 allows a "workspace overflow" denial of service (daemon panic) for shared
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

References

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