Description
Varnish Cache before 7.6.3 and 7.7 before 7.7.1, and Varnish Enterprise before 6.0.13r14, allow client-side desync via HTTP/1 requests, because the product incorrectly permits CRLF to be skipped to delimit chunk boundaries.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| varnish-software | Varnish Cache | < 6.0.14 LTS, 7.0.0 – < 7.6.3, 7.7.0 – < 7.7.1 | 6.0.14 LTS |
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 | 7.7.0-2 | — |
| Debian 12 | varnish | 7.1.1-2+deb12u1 | DSA-5918-1 |
| Debian 11 | varnish | 6.5.1-1+deb11u5 | DLA-4187-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | varnish | No fix yet | — |
| Ubuntu 14.04 LTS | varnish | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | varnish | No fix yet | — |
| Ubuntu Pro 20.04 LTS | varnish | No fix yet | — |
| Ubuntu Pro 18.04 LTS | varnish | No fix yet | — |
| Ubuntu Pro 16.04 LTS | varnish | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | varnish +2 | 7.6.1-2.el10_0.1 | RHSA-2025:8550 |
| RHEL 9 | varnish +2 | 6.6.2-6.el9_6.1 | RHSA-2025:8337 |
| RHEL 8 | varnish +2 | 6.0.13-1.module+el8.10.0+23111+831cc069.1 | RHSA-2025:8336 |
| RHEL 8 | varnish-modules | 0.15.0-6.module+el8.10.0+21682+bcdd3a30 | RHSA-2025:8336 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.4 EUS | varnish +2 | 6.6.2-5.el9_4.1 | RHSA-2025:8349 |
| RHEL 9.2 EUS | varnish +2 | 6.6.2-3.el9_2.3 | RHSA-2025:8351 |
| RHEL 9.0 E4S | varnish +1 | 6.6.2-2.el9_0.4 | RHSA-2025:8350 |
| RHEL 8.8 EUS | varnish +2 | 6.0.8-3.module+el8.8.0+23121+d8c7990e.3 | RHSA-2025:8294 |
| RHEL 8.8 EUS | varnish-modules | 0.15.0-6.module+el8.5.0+11976+0b4af72d | RHSA-2025:8294 |
| RHEL 8.6 TUS | varnish +2 | 6.0.8-2.module+el8.6.0+23122+0639db89.4 | RHSA-2025:8310 |
| RHEL 8.6 TUS | varnish-modules | 0.15.0-6.module+el8.5.0+11976+0b4af72d | RHSA-2025:8310 |
| RHEL 8.6 E4S | varnish +2 | 6.0.8-2.module+el8.6.0+23122+0639db89.4 | RHSA-2025:8310 |
| RHEL 8.6 E4S | varnish-modules | 0.15.0-6.module+el8.5.0+11976+0b4af72d | RHSA-2025:8310 |
| RHEL 8.6 AUS | varnish +2 | 6.0.8-2.module+el8.6.0+23122+0639db89.4 | RHSA-2025:8310 |
| RHEL 8.6 AUS | varnish-modules | 0.15.0-6.module+el8.5.0+11976+0b4af72d | RHSA-2025:8310 |
| RHEL 8.4 TUS | varnish +2 | 6.0.6-2.module+el8.4.0+23123+54dbaab7.6 | RHSA-2025:8340 |
| RHEL 8.4 TUS | varnish-modules | 0.15.0-5.module+el8.3.0+6843+b3b42fcc | RHSA-2025:8340 |
| RHEL 8.4 E4S | varnish +2 | 6.0.6-2.module+el8.4.0+23123+54dbaab7.6 | RHSA-2025:8340 |
| RHEL 8.4 E4S | varnish-modules | 0.15.0-5.module+el8.3.0+6843+b3b42fcc | RHSA-2025:8340 |
| RHEL 8.4 AUS | varnish +2 | 6.0.6-2.module+el8.4.0+23123+54dbaab7.6 | RHSA-2025:8340 |
| RHEL 8.4 AUS | varnish-modules | 0.15.0-5.module+el8.3.0+6843+b3b42fcc | RHSA-2025:8340 |
| RHEL 8.2 AUS | varnish +2 | 6.0.6-1.module+el8.2.0+23124+897a7786.1 | RHSA-2025:8339 |
| RHEL 8.2 AUS | varnish-modules | 0.15.0-4.module+el8+2481+4078e9d2 | RHSA-2025:8339 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | varnish +2 | 7.6.1-2.el10_0.1 | ALSA-2025:8550 |
| AlmaLinux 9 | varnish +2 | 6.6.2-6.el9_6.1 | ALSA-2025:8337 |
| AlmaLinux 8 | varnish +2 | 6.0.13-1.module_el8.10.0+4003+9759c3c1.1 | ALSA-2025:8336 |
| AlmaLinux 8 | varnish-modules | 0.15.0-6.module_el8.9.0+3826+307eaba4 | ALSA-2025:8336 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | varnish | 7.6.1-2.el10_0.1 | RLSA-2025:8550 |
| Rocky Linux 9 | varnish | 6.6.2-6.el9_6.1 | RLSA-2025:8337 |
| Rocky Linux 8 | varnish | 6.0.13-1.module+el8.9.0+1777+0acf9965 | RLSA-2025:8336 |
| Rocky Linux 8 | varnish-modules | 0.15.0-6.module+el8.5.0+677+2a78a869 | RLSA-2025:8336 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | varnish | 7.7.1-r0 | — |
| Alpine v3.23 | varnish | 7.7.1-r0 | — |
| Alpine v3.22 | varnish | 7.7.1-r0 | — |
| Alpine v3.21 | varnish | 7.6.3-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | varnish +2 | 7.6.1-2.el10_0.1 | ELSA-2025-8550 |
| Oracle Linux 9 | varnish +2 | 6.6.2-6.el9_6.1 | ELSA-2025-8337 |
| Oracle Linux 8 | varnish +2 | 6.0.13-1.module+el8.10.0+90594+95ad0b53.1 | ELSA-2025-8336 |
| Oracle Linux 8 | varnish-modules | 0.15.0-6.module+el8.10.0+90594+95ad0b53 | ELSA-2025-8336 |
Advisories 22
- ALSA-2025:8550 Important: varnish security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:8337 Important: varnish security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2025:8336 Important: varnish:6 security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2025-1005 Varnish HTTP Cache: Schwachstelle ermöglicht Manipulation von Dateien BSI CERT-Bund (WID) · Aug 26, 2026
- RHSA-2025:8550 Red Hat Security Advisory: varnish security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8351 Red Hat Security Advisory: varnish security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8349 Red Hat Security Advisory: varnish security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8350 Red Hat Security Advisory: varnish security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8340 Red Hat Security Advisory: varnish:6 security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8336 Red Hat Security Advisory: varnish:6 security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8337 Red Hat Security Advisory: varnish security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8339 Red Hat Security Advisory: varnish:6 security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8310 Red Hat Security Advisory: varnish:6 security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- RHSA-2025:8294 Red Hat Security Advisory: varnish:6 security update Red Hat Security Advisories (RHSA) · Jul 12, 2026
- DSA-5918-1 varnish - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-4187-1 varnish - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2025:8550 Important: varnish security update Rocky Linux Security Advisories · Oct 8, 2025
- RLSA-2025:8337 Important: varnish security update Rocky Linux Security Advisories · Oct 4, 2025
- RLSA-2025:8336 Important: varnish:6 security update Rocky Linux Security Advisories · Jul 29, 2025
- ELSA-2025-8550 Important: varnish security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jun 26, 2025
- ELSA-2025-8337 Important: varnish security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 2, 2025
- ELSA-2025-8336 Important: varnish:6 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jun 2, 2025