Description
Squid is an open source caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Collapse of Data into Unsafe Value bug ,Squid may be vulnerable to a Denial of Service attack against HTTP header parsing. This problem allows a remote client or a remote server to perform Denial of Service when sending oversized headers in HTTP messages. In versions of Squid prior to 6.5 this can be achieved if the request_header_max_size or reply_header_max_size settings are unchanged from the default. In Squid version 6.5 and later, the default setting of these parameters is safe. Squid will emit a critical warning in cache.log if the administrator is setting these parameters to unsafe values. Squid will not at this time prevent these settings from being changed to unsafe values. Users are advised to upgrade to version 6.5. There are no known workarounds for this vulnerability. This issue is also tracked as SQUID-2024:2
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| squid-cache | squid | < 6.5 | — |
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 | 6.5-1 | — |
| Debian 13 | squid | 6.5-1 | — |
| Debian 12 | squid | 5.7-2+deb12u1 | DSA-5637-1 |
| Debian 11 | squid | 4.13-10+deb11u3 | DSA-5637-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | squid | 6.5-1ubuntu1 | — |
| Ubuntu 22.04 LTS | squid | 5.7-0ubuntu0.22.04.4 | USN-6728-1 |
| Ubuntu 20.04 LTS | squid | 4.10-1ubuntu1.10 | USN-6728-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | squid3 | 3.5.27-1ubuntu1.14+esm2 | USN-6857-1 |
| Ubuntu Pro 16.04 LTS | squid3 | 3.5.12-1ubuntu7.16+esm3 | USN-6857-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | squid | 7:5.5-6.el9_3.8 | RHSA-2024:1376 |
| RHEL 8 | libecap +1 | 1.0.1-2.module+el8.9.0+19703+a1da7223 | RHSA-2024:1375 |
| RHEL 8 | squid | 7:4.15-7.module+el8.9.0+21530+59b09a5b.10 | RHSA-2024:1375 |
| RHEL 7 | squid +2 | 7:3.5.20-17.el7_9.10 | RHSA-2024:1787 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.2 EUS | squid | 7:5.5-5.el9_2.5 | RHSA-2024:1184 |
| RHEL 9.0 EUS | squid | 7:5.2-1.el9_0.6 | RHSA-2024:1833 |
| RHEL 8.8 EUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:1062 |
| RHEL 8.8 EUS | squid | 7:4.15-6.module+el8.8.0+21374+5b4927f1.4 | RHSA-2024:1062 |
| RHEL 8.6 EUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:1066 |
| RHEL 8.6 EUS | squid | 7:4.15-3.module+el8.6.0+21376+425c674a.5 | RHSA-2024:1066 |
| RHEL 8.4 TUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:1832 |
| RHEL 8.4 TUS | squid | 7:4.11-4.module+el8.4.0+21523+3cc98f8b.8 | RHSA-2024:1832 |
| RHEL 8.4 E4S | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:1832 |
| RHEL 8.4 E4S | squid | 7:4.11-4.module+el8.4.0+21523+3cc98f8b.8 | RHSA-2024:1832 |
| RHEL 8.4 AUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:1832 |
| RHEL 8.4 AUS | squid | 7:4.11-4.module+el8.4.0+21523+3cc98f8b.8 | RHSA-2024:1832 |
| RHEL 8.2 TUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:2777 |
| RHEL 8.2 TUS | squid | 7:4.4-8.module+el8.2.0+21527+aa63d5ff.9 | RHSA-2024:2777 |
| RHEL 8.2 E4S | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:2777 |
| RHEL 8.2 E4S | squid | 7:4.4-8.module+el8.2.0+21527+aa63d5ff.9 | RHSA-2024:2777 |
| RHEL 8.2 AUS | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2024:2777 |
| RHEL 8.2 AUS | squid | 7:4.4-8.module+el8.2.0+21527+aa63d5ff.9 | RHSA-2024:2777 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | squid | 7:5.5-6.el9_3.8 | ALSA-2024:1376 |
| AlmaLinux 8 | libecap +1 | 1.0.1-2.module_el8.6.0+2741+01592ae8 | ALSA-2024:1375 |
| AlmaLinux 8 | squid | 7:4.15-7.module_el8.9.0+3749+dbf371ed.10 | ALSA-2024:1375 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | libecap | 1.0.1-2.module+el8.9.0+1437+df5ea8f0 | RLSA-2024:1375 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | squid | 5.7-150400.3.26.1 | SUSE-SU-2024:1113-1 |
| SLES 15 SP4 | squid | 5.7-150400.3.26.1 | SUSE-SU-2024:1113-1 |
| SLES 15 SP3 | squid | 4.17-150000.5.52.1 | SUSE-SU-2024:1114-1 |
| SLES 15 SP2 | squid | 4.17-150000.5.52.1 | SUSE-SU-2024:1114-1 |
| SLES 12 SP5 | squid | 4.17-4.44.1 | SUSE-SU-2024:1115-1 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP4 | squid | 5.7-150400.3.26.1 | SUSE-SU-2024:1113-1 |
| SLES for SAP 15 SP3 | squid | 4.17-150000.5.52.1 | SUSE-SU-2024:1114-1 |
| SLES for SAP 15 SP2 | squid | 4.17-150000.5.52.1 | SUSE-SU-2024:1114-1 |
| SLES for SAP 12 SP5 | squid | 4.17-4.44.1 | SUSE-SU-2024:1115-1 |
| SLE HPC 15 SP4 | squid | 5.7-150400.3.26.1 | SUSE-SU-2024:1113-1 |
| SLE HPC 15 SP3 | squid | 4.17-150000.5.52.1 | SUSE-SU-2024:1114-1 |
| SLE HPC 15 SP2 | squid | 4.17-150000.5.52.1 | SUSE-SU-2024:1114-1 |
| SUSE Manager Server 4.3 | squid | 5.7-150400.3.26.1 | SUSE-SU-2024:1113-1 |
| SUSE Manager Proxy 4.3 | squid | 5.7-150400.3.26.1 | SUSE-SU-2024:1113-1 |
| SUSE Enterprise Storage 7.1 | squid | 4.17-150000.5.52.1 | SUSE-SU-2024:1114-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | squid | 6.8-1.1 | openSUSE-SU-2024:13757-1 |
| openSUSE Leap 15.5 | squid | 5.7-150400.3.26.1 | SUSE-SU-2024:1113-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | squid | 7:5.8-1.amzn2023.0.3 | ALAS2023-2023-445 |
| Amazon Linux 2 | squid +2 | 7:3.5.20-17.amzn2.7.11 | ALAS2-2024-2382 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | squid | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | squid | 7:5.5-6.0.1.el9_3.8 | ELSA-2024-1376 |
| Oracle Linux 8 | libecap +1 | 1.0.1-2.module+el8.9.0+90083+f7556140 | ELSA-2024-1375 |
| Oracle Linux 8 | squid | 7:4.15-7.module+el8.9.0+90184+ff65e696.10 | ELSA-2024-1375 |
| Oracle Linux 7 | squid +2 | 7:3.5.20-17.0.1.el7_9.10 | ELSA-2024-1787 |
Advisories 26
- ALSA-2024:1376 Important: squid security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2024:1375 Important: squid:4 security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2024:2777 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2024:1833 Red Hat Security Advisory: squid security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2024:1832 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2024:1375 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2024:1376 Red Hat Security Advisory: squid security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2024:1787 Red Hat Security Advisory: squid security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2024:1184 Red Hat Security Advisory: squid security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2024:1066 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2024:1062 Red Hat Security Advisory: squid:4 security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-6857-1 squid3 vulnerabilities Ubuntu Security Notices (USN) · Jun 25, 2026
- USN-6728-1 squid vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- WID-SEC-2024-0396 Squid: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Apr 19, 2026
- DSA-5637-1 squid - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:13757-1 squid-6.8-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:1114-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:1115-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2024:1113-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- RLSA-2024:1375 Important: squid:4 security update Rocky Linux Security Advisories · May 7, 2025
- WID-SEC-2024-1248 Xerox FreeFlow Print Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 21, 2024
- ELSA-2024-1787 Important: squid security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 11, 2024
- ELSA-2024-1375 Important: squid:4 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Mar 21, 2024
- ELSA-2024-1376 Important: squid security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Mar 20, 2024
- ALAS2023-2023-445 Moderate: squid security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Feb 29, 2024
- ALAS2-2024-2382 Moderate: squid security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Feb 29, 2024