CVE-2021-31808

An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to an input-validation bug, it is vulnerable to a Denial of Service attack (against all clients using the proxy). A client sends an HTTP Range request to trigger this.

• CWE-190

• http://seclists.org/fulldisclosure/2023/Oct/14Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/10/11/3Mailing List, Third Party Advisory
• http://www.squid-cache.org/Versions/v4/changesets/squid-4-e7cf864f938f24eea8af0692c04d16790983c823.patchExploit, Patch, Vendor Advisory
• https://github.com/squid-cache/squid/security/advisories/GHSA-pxwq-f3qr-w2xfPatch, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2021/06/msg00014.htmlMailing List, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/
• https://security.netapp.com/advisory/ntap-20210716-0007/Third Party Advisory
• https://www.debian.org/security/2021/dsa-4924Third Party Advisory
• http://seclists.org/fulldisclosure/2023/Oct/14Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/10/11/3Mailing List, Third Party Advisory
• http://www.squid-cache.org/Versions/v4/changesets/squid-4-e7cf864f938f24eea8af0692c04d16790983c823.patchExploit, Patch, Vendor Advisory
• https://github.com/squid-cache/squid/security/advisories/GHSA-pxwq-f3qr-w2xfPatch, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2021/06/msg00014.htmlMailing List, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/
• https://security.netapp.com/advisory/ntap-20210716-0007/Third Party Advisory
• https://www.debian.org/security/2021/dsa-4924Third Party Advisory

Published

May 27, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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