squid: An issue was discovered in Squid before 4.15 and 5.x before 5.0.6
CVE-2021-31808 is fixed in 9 products on 1 platform, first by squid 3.5.27-1ubuntu1.11, released May 28, 2021. It is not reported as exploited. Patch Radar priority: Routine.
An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due toan input-validation bug, it is vulnerable to a Denial of Service attack(against all clients using the proxy). A client sends an HTTP Range requestto trigger this.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| libecap · RHEL 8 | 0:1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2021:4292 | Nov 9, 2021 |
| libecap · ol 8 | 0:1.0.1-2.module+el8.3.0+7819+eb7d4ef6 | ELSA-2021-4292 | Nov 16, 2021 |
| libecap-devel · RHEL 8 | 0:1.0.1-2.module+el8.1.0+4044+36416a77 | RHSA-2021:4292 | Nov 9, 2021 |
| libecap-devel · ol 8 | 0:1.0.1-2.module+el8.3.0+7819+eb7d4ef6 | ELSA-2021-4292 | Nov 16, 2021 |
| squid · RHEL 8 | 7:4.15-1.module+el8.5.0+11469+24c223d9 | RHSA-2021:4292 | Nov 9, 2021 |
| squid · Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.11 | squid 3.5.27-1ubuntu1.11 | May 28, 2021 |
| squid · Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.4 | squid 4.10-1ubuntu1.4 | May 28, 2021 |
| squid · Ubuntu 24.10 (oracular) | 4.13-10ubuntu1 | squid 4.13-10ubuntu1 | Jan 16, 2026 |
| squid · Ubuntu 25.04 (plucky) | 4.13-10ubuntu1 | squid 4.13-10ubuntu1 | Jan 16, 2026 |
| squid · ol 8 | 7:4.15-1.module+el8.5.0+20327+24c223d9 | ELSA-2021-4292 | Nov 16, 2021 |
| squid-cgi · Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.11 | squid-cgi 3.5.27-1ubuntu1.11 | May 28, 2021 |
| squid-cgi · Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.4 | squid-cgi 4.10-1ubuntu1.4 | May 28, 2021 |
| squid-cgi · Ubuntu 24.10 (oracular) | 4.13-10ubuntu1 | squid-cgi 4.13-10ubuntu1 | Jan 16, 2026 |
| squid-cgi · Ubuntu 25.04 (plucky) | 4.13-10ubuntu1 | squid-cgi 4.13-10ubuntu1 | Jan 16, 2026 |
| squid-common · Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.11 | squid-common 3.5.27-1ubuntu1.11 | May 28, 2021 |
| squid-common · Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.4 | squid-common 4.10-1ubuntu1.4 | May 28, 2021 |
| squid-common · Ubuntu 24.10 (oracular) | 4.13-10ubuntu1 | squid-common 4.13-10ubuntu1 | Jan 16, 2026 |
| squid-common · Ubuntu 25.04 (plucky) | 4.13-10ubuntu1 | squid-common 4.13-10ubuntu1 | Jan 16, 2026 |
| squid-openssl · Ubuntu 24.10 (oracular) | 4.13-10ubuntu1 | squid-openssl 4.13-10ubuntu1 | Jan 16, 2026 |
| squid-openssl · Ubuntu 25.04 (plucky) | 4.13-10ubuntu1 | squid-openssl 4.13-10ubuntu1 | Jan 16, 2026 |
| squid-purge · Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.11 | squid-purge 3.5.27-1ubuntu1.11 | May 28, 2021 |
| squid-purge · Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.4 | squid-purge 4.10-1ubuntu1.4 | May 28, 2021 |
| squid-purge · Ubuntu 24.10 (oracular) | 4.13-10ubuntu1 | squid-purge 4.13-10ubuntu1 | Jan 16, 2026 |
| squid-purge · Ubuntu 25.04 (plucky) | 4.13-10ubuntu1 | squid-purge 4.13-10ubuntu1 | Jan 16, 2026 |
| squid3 · Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.11 | squid3 3.5.27-1ubuntu1.11 | May 28, 2021 |
| squidclient · Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.11 | squidclient 3.5.27-1ubuntu1.11 | May 28, 2021 |
| squidclient · Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.4 | squidclient 4.10-1ubuntu1.4 | May 28, 2021 |
| squidclient · Ubuntu 24.10 (oracular) | 4.13-10ubuntu1 | squidclient 4.13-10ubuntu1 | Jan 16, 2026 |
| squidclient · Ubuntu 25.04 (plucky) | 4.13-10ubuntu1 | squidclient 4.13-10ubuntu1 | Jan 16, 2026 |
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