# CVE-2021-28116: squid: Squid through 4.14 and 5.x through 5.0.5, in some configurations, allowsinformation disclosure because of an out-of-b...

CVE-2021-28116 is fixed in 9 products on 1 platform, first by squid 3.5.27-1ubuntu1.12, released March 9, 2021. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-28116
- Priority: Routine
- CVSS: 5.3 (Medium)
- EPSS: 0.1295
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 9, 2021

## Description

Squid through 4.14 and 5.x through 5.0.5, in some configurations, allowsinformation disclosure because of an out-of-bounds read in WCCP protocoldata. This can be leveraged as part of a chain for remote code execution asnobody.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libecap RHEL 8 | 0:1.0.1-2.module+el8.1.0+4044+36416a77 | [RHSA-2022:1939](https://patchblox.com/security/data/fix/linux/rhsa-2022-1939.md) | May 10, 2022 |
| Linux | libecap almalinux 8 | 1.0.1-2.module_el8.6.0+2741+01592ae8 | [ALSA-2022:1939](https://patchblox.com/security/data/fix/linux/alsa-2022-1939.md) | May 10, 2022 |
| Linux | libecap ol 8 | 0:1.0.1-2.module+el8.3.0+7819+eb7d4ef6 | [ELSA-2022-1939](https://patchblox.com/security/data/fix/linux/elsa-2022-1939.md) | May 17, 2022 |
| Linux | libecap rocky 8 | 0:1.0.1-2.module+el8.4.0+404+316a0dc5 | [RLSA-2022:1939](https://patchblox.com/security/data/fix/linux/rlsa-2022-1939.md) | May 10, 2022 |
| Linux | libecap-devel RHEL 8 | 0:1.0.1-2.module+el8.1.0+4044+36416a77 | [RHSA-2022:1939](https://patchblox.com/security/data/fix/linux/rhsa-2022-1939.md) | May 10, 2022 |
| Linux | libecap-devel almalinux 8 | 1.0.1-2.module_el8.6.0+2741+01592ae8 | [ALSA-2022:1939](https://patchblox.com/security/data/fix/linux/alsa-2022-1939.md) | May 10, 2022 |
| Linux | libecap-devel ol 8 | 0:1.0.1-2.module+el8.3.0+7819+eb7d4ef6 | [ELSA-2022-1939](https://patchblox.com/security/data/fix/linux/elsa-2022-1939.md) | May 17, 2022 |
| Linux | squid Debian 11.6 (bullseye) | 4.13-10+deb11u1 | [DSA-5171-1](https://patchblox.com/security/data/fix/linux/dsa-5171-1.md) | Jun 27, 2022 |
| Linux | squid RHEL 8 | 7:4.15-3.module+el8.6.0+14176+9782b8ab | [RHSA-2022:1939](https://patchblox.com/security/data/fix/linux/rhsa-2022-1939.md) | May 10, 2022 |
| Linux | squid Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.12 | [squid 3.5.27-1ubuntu1.12](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-3.5.27-1ubuntu1.12.md) | Mar 9, 2021 |
| Linux | squid Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.5 | [squid 4.10-1ubuntu1.5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-4.10-1ubuntu1.5.md) | Mar 9, 2021 |
| Linux | squid Ubuntu 22.04.1 LTS (jammy) | 4.13-10ubuntu5 | [squid 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-4.13-10ubuntu5.md) | Mar 9, 2021 |
| Linux | squid Ubuntu 24.10 (oracular) | 4.13-10ubuntu5 | [squid 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-squid-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid Ubuntu 25.04 (plucky) | 4.13-10ubuntu5 | [squid 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-squid-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid almalinux 8 | 7:4.15-3.module_el8.6.0+2741+01592ae8 | [ALSA-2022:1939](https://patchblox.com/security/data/fix/linux/alsa-2022-1939.md) | May 10, 2022 |
| Linux | squid ol 8 | 7:4.15-3.module+el8.6.0+20529+9782b8ab | [ELSA-2022-1939](https://patchblox.com/security/data/fix/linux/elsa-2022-1939.md) | May 17, 2022 |
| Linux | squid rocky 8 | 7:4.15-3.module+el8.6.0+1044+67ab5d0a.2 | [RLSA-2022:1939](https://patchblox.com/security/data/fix/linux/rlsa-2022-1939.md) | May 10, 2022 |
| Linux | squid-cgi Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.12 | [squid-cgi 3.5.27-1ubuntu1.12](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-cgi-3.5.27-1ubuntu1.12.md) | Mar 9, 2021 |
| Linux | squid-cgi Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.5 | [squid-cgi 4.10-1ubuntu1.5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-cgi-4.10-1ubuntu1.5.md) | Mar 9, 2021 |
| Linux | squid-cgi Ubuntu 22.04.1 LTS (jammy) | 4.13-10ubuntu5 | [squid-cgi 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-cgi-4.13-10ubuntu5.md) | Mar 9, 2021 |
| Linux | squid-cgi Ubuntu 24.10 (oracular) | 4.13-10ubuntu5 | [squid-cgi 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-squid-cgi-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid-cgi Ubuntu 25.04 (plucky) | 4.13-10ubuntu5 | [squid-cgi 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-squid-cgi-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid-common Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.12 | [squid-common 3.5.27-1ubuntu1.12](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-common-3.5.27-1ubuntu1.12.md) | Mar 9, 2021 |
| Linux | squid-common Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.5 | [squid-common 4.10-1ubuntu1.5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-common-4.10-1ubuntu1.5.md) | Mar 9, 2021 |
| Linux | squid-common Ubuntu 22.04.1 LTS (jammy) | 4.13-10ubuntu5 | [squid-common 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-common-4.13-10ubuntu5.md) | Mar 9, 2021 |
| Linux | squid-common Ubuntu 24.10 (oracular) | 4.13-10ubuntu5 | [squid-common 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-squid-common-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid-common Ubuntu 25.04 (plucky) | 4.13-10ubuntu5 | [squid-common 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-squid-common-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid-openssl Ubuntu 22.04.1 LTS (jammy) | 4.13-10ubuntu5 | [squid-openssl 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-openssl-4.13-10ubuntu5.md) | Mar 9, 2021 |
| Linux | squid-openssl Ubuntu 24.10 (oracular) | 4.13-10ubuntu5 | [squid-openssl 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-squid-openssl-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid-openssl Ubuntu 25.04 (plucky) | 4.13-10ubuntu5 | [squid-openssl 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-squid-openssl-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid-purge Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.12 | [squid-purge 3.5.27-1ubuntu1.12](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid-purge-3.5.27-1ubuntu1.12.md) | Mar 9, 2021 |
| Linux | squid-purge Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.5 | [squid-purge 4.10-1ubuntu1.5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squid-purge-4.10-1ubuntu1.5.md) | Mar 9, 2021 |
| Linux | squid-purge Ubuntu 22.04.1 LTS (jammy) | 4.13-10ubuntu5 | [squid-purge 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squid-purge-4.13-10ubuntu5.md) | Mar 9, 2021 |
| Linux | squid-purge Ubuntu 24.10 (oracular) | 4.13-10ubuntu5 | [squid-purge 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-squid-purge-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid-purge Ubuntu 25.04 (plucky) | 4.13-10ubuntu5 | [squid-purge 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-squid-purge-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squid3 Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.12 | [squid3 3.5.27-1ubuntu1.12](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squid3-3.5.27-1ubuntu1.12.md) | Mar 9, 2021 |
| Linux | squidclient Ubuntu 18.04.6 LTS (bionic) | 3.5.27-1ubuntu1.12 | [squidclient 3.5.27-1ubuntu1.12](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-squidclient-3.5.27-1ubuntu1.12.md) | Mar 9, 2021 |
| Linux | squidclient Ubuntu 20.04 LTS (focal) | 4.10-1ubuntu1.5 | [squidclient 4.10-1ubuntu1.5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-squidclient-4.10-1ubuntu1.5.md) | Mar 9, 2021 |
| Linux | squidclient Ubuntu 22.04.1 LTS (jammy) | 4.13-10ubuntu5 | [squidclient 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-squidclient-4.13-10ubuntu5.md) | Mar 9, 2021 |
| Linux | squidclient Ubuntu 24.10 (oracular) | 4.13-10ubuntu5 | [squidclient 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-squidclient-4.13-10ubuntu5.md) | Jan 16, 2026 |
| Linux | squidclient Ubuntu 25.04 (plucky) | 4.13-10ubuntu5 | [squidclient 4.13-10ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-squidclient-4.13-10ubuntu5.md) | Jan 16, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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