Description
An issue was discovered in Varnish Cache before 6.0.5 LTS, 6.1.x and 6.2.x before 6.2.2, and 6.3.x before 6.3.1. It does not clear a pointer between the handling of one client request and the next request within the same connection. This sometimes causes information to be disclosed from the connection workspace, such as data structures associated with previous requests within this connection or VCL-related temporary headers.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 13 | varnish | 6.4.0-1 | — |
| Debian 12 | varnish | 6.4.0-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | varnish | 6.6.1-1ubuntu0.2 | USN-5474-1 |
| Ubuntu 20.04 LTS | varnish | 6.2.1-2ubuntu0.1 | USN-5474-1 |
| Ubuntu 18.04 LTS | varnish | 5.2.1-1ubuntu0.1 | USN-5474-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | varnish +2 | 6.0.6-2.module+el8.3.0+6843+b3b42fcc | RHSA-2020:4756 |
| RHEL 8 | varnish-modules | 0.15.0-5.module+el8.3.0+6843+b3b42fcc | RHSA-2020:4756 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | varnish | 6.0.6-2.module+el8.3.0+179+20b582cc | RLSA-2020:4756 |
| Rocky Linux 8 | varnish-modules | 0.15.0-5.module+el8.3.0+179+20b582cc | RLSA-2020:4756 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP1 | varnish | 6.2.1-bp151.4.6.1 | openSUSE-SU-2020:0819-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | varnish | 6.2.1-lp151.3.6.1 | openSUSE-SU-2020:0808-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | varnish +2 | 6.0.6-2.module+el8.3.0+7653+45014445 | ELSA-2020-4756 |
| Oracle Linux 8 | varnish-modules | 0.15.0-5.module+el8.3.0+7653+45014445 | ELSA-2020-4756 |
Advisories 7
- RHSA-2020:4756 Red Hat Security Advisory: varnish:6 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- USN-5474-1 varnish vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- RLSA-2020:4756 Moderate: varnish:6 security, bug fix, and enhancement update Rocky Linux Security Advisories · Feb 5, 2026
- openSUSE-SU-2020:0808-1 Security update for varnish SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0819-1 Security update for varnish SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2022-0193 Red Hat Enterprise Linux: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 27, 2023
- ELSA-2020-4756 Moderate: varnish:6 security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 10, 2020
References
- http://varnish-cache.org/security/VSV00004.html#vsv00004
- openSUSE-SU-2020:0819 vendor-advisory
- openSUSE-SU-2020:0808 vendor-advisory