Description
In Squid 3.x through 3.5.28, 4.x through 4.17, and 5.x before 5.6, due to improper buffer management, a Denial of Service can occur when processing long Gopher server responses.
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 14 | squid | 5.6-1 | — |
| Debian 13 | squid | 5.6-1 | — |
| Debian 12 | squid | 5.6-1 | — |
| Debian 11 | squid | 4.13-10+deb11u1 | DSA-5171-1 |
| Debian 10 | squid | 4.6-1+deb10u7 | DSA-5171-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | squid | 5.2-1ubuntu4.1 | USN-5491-1 |
| Ubuntu 20.04 LTS | squid | 4.10-1ubuntu1.6 | USN-5491-1 |
| Ubuntu 18.04 LTS | squid3 | 3.5.27-1ubuntu1.13 | USN-5491-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | squid3 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | squid | 7:5.2-1.el9_0.1 | RHSA-2022:5527 |
| RHEL 8 | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2022:5526 |
| RHEL 8 | squid | 7:4.15-3.module+el8.6.0+15801+8fa20c64.1 | RHSA-2022:5526 |
| RHEL 7 | squid +2 | 7:3.5.20-17.el7_9.7 | RHSA-2022:5542 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.4 EUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2022:5528 |
| RHEL 8.4 EUS | squid | 7:4.11-4.module+el8.4.0+15802+77c2cdda.3 | RHSA-2022:5528 |
| RHEL 8.2 EUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2022:5529 |
| RHEL 8.2 EUS | squid | 7:4.4-8.module+el8.2.0+15803+1b4cda03.4 | RHSA-2022:5529 |
| RHEL 8.1 E4S | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2022:5530 |
| RHEL 8.1 E4S | squid | 7:4.4-8.module+el8.1.0+15805+9a5539dc.4 | RHSA-2022:5530 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | squid | 7:5.2-1.el9_0.1 | ALSA-2022:5527 |
| AlmaLinux 8 | libecap +1 | 1.0.1-2.module_el8.6.0+2741+01592ae8 | ALSA-2022:5526 |
| AlmaLinux 8 | squid | 7:4.15-3.module_el8.6.0+3010+383bc947.1 | ALSA-2022:5526 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | libecap | 1.0.1-2.module+el8.4.0+404+316a0dc5 | RLSA-2022:5526 |
| Rocky Linux 8 | squid | 7:4.15-3.module+el8.6.0+1044+67ab5d0a.2 | RLSA-2022:5526 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP4 | squid | 5.6-150400.3.3.1 | SUSE-SU-2022:2359-1 |
| SLES 15 SP3 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLES 15 SP2 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLES 15 SP1 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLES 15 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
Show 19 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | squid | 4.17-4.24.1 | SUSE-SU-2022:2367-1 |
| SLES 12 SP4 | squid | 3.5.21-26.35.1 | SUSE-SU-2022:2392-1 |
| SLES 12 SP3 | squid | 3.5.21-26.35.1 | SUSE-SU-2022:2392-1 |
| SLES 12 SP2 | squid | 3.5.21-26.35.1 | SUSE-SU-2022:2392-1 |
| SLES for SAP 15 SP2 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLES for SAP 15 SP1 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLES for SAP 15 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLES for SAP 12 SP5 | squid | 4.17-4.24.1 | SUSE-SU-2022:2367-1 |
| SLES for SAP 12 SP4 | squid | 3.5.21-26.35.1 | SUSE-SU-2022:2392-1 |
| SLE HPC 15 SP2 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLE HPC 15 SP1 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SLE HPC 15 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SUSE OpenStack Cloud Crowbar 9 | squid | 3.5.21-26.35.1 | SUSE-SU-2022:2392-1 |
| SUSE OpenStack Cloud 9 | squid | 3.5.21-26.35.1 | SUSE-SU-2022:2392-1 |
| SUSE Manager Server 4.1 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SUSE Manager Retail Branch Server 4.1 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SUSE Manager Proxy 4.1 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SUSE Enterprise Storage 7 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
| SUSE Enterprise Storage 6 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | squid | 5.6-1.1 | openSUSE-SU-2024:12157-1 |
| openSUSE Leap 15.4 | squid | 5.6-150400.3.3.1 | SUSE-SU-2022:2359-1 |
| openSUSE Leap 15.3 | squid | 4.17-150000.5.32.1 | SUSE-SU-2022:2553-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | squid +2 | 7:3.5.20-17.amzn2.7.1 | ALAS2-2023-1907 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | squid | 7:5.2-1.el9_0.1 | ELSA-2022-5527 |
| Oracle Linux 8 | libecap +1 | 1.0.1-2.module+el8.3.0+7819+eb7d4ef6 | ELSA-2022-5526 |
| Oracle Linux 8 | squid | 7:4.15-3.module+el8.6.0+20699+8fa0a254.1 | ELSA-2022-5526 |
| Oracle Linux 7 | squid +2 | 7:3.5.20-17.0.1.el7_9.7 | ELSA-2022-5542 |
Advisories 22
- ALSA-2022:5527 Important: squid security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2022:5526 Important: squid:4 security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2023-2917 Xerox FreeFlow Print Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 30, 2026
- RHSA-2022:5542 Red Hat Security Advisory: squid security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-5491-1 squid, squid3 vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-5171-1 squid - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2022:5526 Important: squid:4 security update Rocky Linux Security Advisories · Feb 5, 2026
- SUSE-SU-2022:2392-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:2359-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:12157-1 squid-5.6-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:2553-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:2367-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2022:5529 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:5530 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:5528 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:5527 Red Hat Security Advisory: squid security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2022:5526 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- WID-SEC-2022-0385 Squid: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Nov 18, 2025
- ALAS2-2023-1907 Important: squid security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jan 20, 2023
- ELSA-2022-5542 Important: squid security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jul 12, 2022
- ELSA-2022-5526 Important: squid:4 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jul 8, 2022
- ELSA-2022-5527 Important: squid security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 7, 2022
References
- https://github.com/squid-cache/squid/commit/5e2ea2b13bd98f53e29964ca26bb0d602a8a12b9
- http://www.squid-cache.org/Versions/v4/changesets/SQUID-2021_7.patch
- http://www.squid-cache.org/Versions/v5/changesets/SQUID-2021_7.patch
- https://github.com/squid-cache/squid/security/advisories/GHSA-f5cp-6rh3-284w
- https://security-tracker.debian.org/tracker/CVE-2021-46784
- https://security.netapp.com/advisory/ntap-20221223-0007/
- [oss-security] 20231013 Re: Squid Caching Proxy Security Audit: 55 Vulnerabilities, 35 0days. mailing-list
- [oss-security] 20231013 Re: Squid Caching Proxy Security Audit: 55 Vulnerabilities, 35 0days. mailing-list
- [oss-security] 20231021 Re: Squid Caching Proxy Security Audit: 55 Vulnerabilities, 35 0days. mailing-list