Description
An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker can connect to HTTP servers that only listen on localhost.
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 | 4.9-1 | — |
| Debian 13 | squid | 4.9-1 | — |
| Debian 12 | squid | 4.9-1 | — |
| Debian 10 | squid | 4.6-1+deb10u2 | DSA-4682-1 |
| Debian 9 | squid3 | 3.5.23-5+deb9u2 | DLA-2278-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | squid | 4.9-2ubuntu1 | — |
| Ubuntu 18.04 LTS | squid3 | 3.5.27-1ubuntu1.7 | USN-4446-1, USN-4213-1 |
| Ubuntu 16.04 LTS | squid3 | 3.5.12-1ubuntu7.12 | USN-4446-1, USN-4213-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | libecap +1 | 1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2020:4743 |
| RHEL 8 | squid | 7:4.11-3.module+el8.3.0+7851+7808b5f9 | RHSA-2020:4743 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | libecap +1 | 1.0.1-2.module_el8.6.0+2741+01592ae8 | ALSA-2020:4743 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | libecap | 1.0.1-2.module+el8.4.0+404+316a0dc5 | RLSA-2020:4743 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | squid | 4.9-5.11.1 | SUSE-SU-2019:2975-1 |
| SLES 15 | squid | 4.9-5.11.1 | SUSE-SU-2019:2975-1 |
| SLES 12 SP5 | squid | 4.9-4.3.2 | SUSE-SU-2019:3067-1 |
| SLES 12 SP4 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SLES 12 SP3 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SLES 11 SP4 | squid | 2.7.STABLE5-2.12.30.6.1 | SUSE-SU-2022:14908-1 |
| SLES 11 SP4 | squid3 | 3.1.23-8.16.37.12.1 | SUSE-SU-2020:14460-1 |
| SLES for SAP 12 SP5 | squid | 4.9-4.3.2 | SUSE-SU-2019:3067-1 |
| SLES for SAP 12 SP4 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SLES for SAP 12 SP3 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SLES for SAP 12 SP2 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SUSE OpenStack Cloud Crowbar 8 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SUSE OpenStack Cloud 8 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SUSE OpenStack Cloud 7 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | squid | 2.7.STABLE5-2.12.30.6.1 | SUSE-SU-2022:14908-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | squid3 | 3.1.23-8.16.37.12.1 | SUSE-SU-2020:14460-1 |
| SUSE HPE Helion OpenStack 8 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
| SUSE Enterprise Storage 5 | squid | 3.5.21-26.20.1 | SUSE-SU-2020:0661-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | squid | 4.16-1.5 | openSUSE-SU-2024:11403-1 |
| openSUSE Leap 15.1 | squid | 4.9-lp151.2.7.1 | openSUSE-SU-2019:2541-1 |
| openSUSE Leap 15.0 | squid | 4.9-lp150.13.1 | openSUSE-SU-2019:2540-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | squid +2 | 7:3.5.20-17.amzn2.7.5 | ALAS2-2023-2065 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | libecap +1 | 1.0.1-2.module+el8.3.0+7819+eb7d4ef6 | ELSA-2020-4743 |
| Oracle Linux 8 | squid | 7:4.11-3.module+el8.3.0+7819+eb7d4ef6 | ELSA-2020-4743 |
| Oracle Linux 7 | squid | 7:4.11-3.0.1.el7 | ELSA-2022-22254 |
Advisories 19
- ALSA-2020:4743 Moderate: squid:4 security, bug fix, and enhancement update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2020:4743 Red Hat Security Advisory: squid:4 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jul 4, 2026
- DSA-4682-1 squid - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2278-1 squid3 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-4446-1 squid3 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-4213-1 squid, squid3 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- RLSA-2020:4743 Moderate: squid:4 security, bug fix, and enhancement update Rocky Linux Security Advisories · Feb 4, 2026
- openSUSE-SU-2024:11403-1 squid-4.16-1.5 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0661-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:2541-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:3067-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:14908-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:2975-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:2540-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14460-1 Security update for squid3 SUSE / openSUSE Security Updates · May 2, 2025
- WID-SEC-2022-1592 Squid: Mehrere Schwachstellen ermöglichen Umgehung von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Feb 11, 2024
- ALAS2-2023-2065 Important: squid security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jun 1, 2023
- ELSA-2022-22254 Important: squid security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 3, 2022
- ELSA-2020-4743 Moderate: squid:4 security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 10, 2020
References
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00056.html
- http://www.squid-cache.org/Advisories/SQUID-2019_8.txt
- https://bugzilla.suse.com/show_bug.cgi?id=1156329
- USN-4213-1 vendor-advisory
- FEDORA-2019-0b16cbdd0e vendor-advisory
- FEDORA-2019-9538783033 vendor-advisory
- DSA-4682 vendor-advisory
- [debian-lts-announce] 20200710 [SECURITY] [DLA 2278-1] squid3 security update mailing-list
- USN-4446-1 vendor-advisory