Description
An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP request with a Content-Length header containing "+\ "-" or an uncommon shell whitespace character prefix to the length field-value.
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 | 4.12-1 | — |
| Debian 13 | squid | 4.12-1 | — |
| Debian 12 | squid | 4.12-1 | — |
| Debian 10 | squid | 4.6-1+deb10u3 | DSA-4732-1 |
| Debian 9 | squid3 | 3.5.23-5+deb9u5 | DLA-2394-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | squid | 4.10-1ubuntu1.3 | USN-4895-1 |
| Ubuntu 18.04 LTS | squid3 | 3.5.27-1ubuntu1.9 | USN-4895-1, USN-4551-1 |
| Ubuntu 16.04 LTS | squid3 | 3.5.12-1ubuntu7.15 | USN-4895-1, USN-4551-1 |
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 |
| RHEL 7 | squid +2 | 7:3.5.20-17.el7_9.4 | RHSA-2020:4082 |
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 SP2 | squid | 4.13-5.23.1 | SUSE-SU-2020:2442-1 |
| SLES 15 SP1 | squid | 4.13-5.23.1 | SUSE-SU-2020:2442-1 |
| SLES 15 | squid | 4.13-5.23.1 | SUSE-SU-2020:2442-1 |
| SLES 12 SP5 | squid | 4.13-4.15.1 | SUSE-SU-2020:2443-1 |
| SLES 12 SP4 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
Show 17 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SLES 12 SP2 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SLES 11 SP4 | squid3 | 3.1.23-8.16.37.12.1 | SUSE-SU-2020:14460-1 |
| SLES for SAP 15 | squid | 4.13-5.23.1 | SUSE-SU-2020:2442-1 |
| SLES for SAP 12 SP5 | squid | 4.13-4.15.1 | SUSE-SU-2020:2443-1 |
| SLES for SAP 12 SP4 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SLES for SAP 12 SP3 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SLES for SAP 12 SP2 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SLE HPC 15 | squid | 4.13-5.23.1 | SUSE-SU-2020:2442-1 |
| SUSE OpenStack Cloud Crowbar 9 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SUSE OpenStack Cloud Crowbar 8 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SUSE OpenStack Cloud 9 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SUSE OpenStack Cloud 8 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SUSE OpenStack Cloud 7 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| 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 | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
| SUSE Enterprise Storage 5 | squid | 3.5.21-26.29.1 | SUSE-SU-2020:1946-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | squid | 4.16-1.5 | openSUSE-SU-2024:11403-1 |
| openSUSE Leap 15.2 | squid | 4.13-lp152.2.6.1 | openSUSE-SU-2020:1369-1 |
| openSUSE Leap 15.1 | squid | 4.13-lp151.2.24.1 | openSUSE-SU-2020:1346-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | squid | 4.12.0-r0 | — |
| Alpine v3.23 | squid | 4.12.0-r0 | — |
| Alpine v3.22 | squid | 4.12.0-r0 | — |
| Alpine v3.21 | squid | 4.12.0-r0 | — |
| Alpine v3.20 | squid | 4.12.0-r0 | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | squid | 4.12.0-r0 | — |
| Alpine v3.18 | squid | 4.12.0-r0 | — |
| Alpine v3.17 | squid | 4.12.0-r0 | — |
| Alpine v3.16 | squid | 4.12.0-r0 | — |
| Alpine v3.15 | squid | 4.12.0-r0 | — |
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 +2 | 7:3.5.20-17.el7_9.4 | ELSA-2020-4082 |
Advisories 17
- 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
- RHSA-2020:4082 Red Hat Security Advisory: squid security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-4732-1 squid - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2394-1 squid3 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-4895-1 squid, squid3 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-4551-1 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
- SUSE-SU-2020:2443-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2442-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11403-1 squid-4.16-1.5 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1346-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1369-1 Security update for squid SUSE / openSUSE Security Updates · May 7, 2025
- SUSE-SU-2020:1946-1 Security update for squid SUSE / openSUSE Security Updates · May 2, 2025
- SUSE-SU-2020:14460-1 Security update for squid3 SUSE / openSUSE Security Updates · May 2, 2025
- ELSA-2020-4743 Moderate: squid:4 security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 10, 2020
- ELSA-2020-4082 Important: squid security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 8, 2020
References
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-ea12a34d338b962707d5078d6d1fc7c6eb119a22.patch
- http://www.squid-cache.org/Versions/v5/changesets/squid-5-485c9a7bb1bba88754e07ad0094647ea57a6eb8d.patch
- https://github.com/squid-cache/squid/security/advisories/GHSA-qf3v-rc95-96j5
- FEDORA-2020-cbebc5617e vendor-advisory
- DSA-4732 vendor-advisory
- openSUSE-SU-2020:1346 vendor-advisory
- openSUSE-SU-2020:1369 vendor-advisory
- USN-4551-1 vendor-advisory
- [debian-lts-announce] 20201002 [SECURITY] [DLA 2394-1] squid3 security update mailing-list
- https://security.netapp.com/advisory/ntap-20210312-0001/