CVE-2019-18678An 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…
- 5.3MediumCVSS base score
- 6.2%Exploitation in 30 daysEPSS · top 6.4% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mitre
- 22 days later
· 22 days later
Published
- 5 years later
· 5 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 6.2% · top 6.4% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Affected products
n/a
- affected n/a
References
References11
- https://github.com/squid-cache/squid/pull/445 (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.suse.com/show_bug.cgi?id=1156323 (opens in a new tab)x_refsource_CONFIRMx_transferred
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-671ba97abe929156dc4c717ee52ad22fba0f7443.patch (opens in a new tab)x_refsource_CONFIRMx_transferred
- http://www.squid-cache.org/Advisories/SQUID-2019_10.txt (opens in a new tab)x_refsource_CONFIRMx_transferred
- USN-4213-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- FEDORA-2019-0b16cbdd0e (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2019-9538783033 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- [debian-lts-announce] 20191210 [SECURITY] [DLA 2028-1] squid3 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- GLSA-202003-34 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- DSA-4682 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- [debian-lts-announce] 20200710 [SECURITY] [DLA 2278-1] squid3 security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2019-8394 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2019-18678)Record last updated .