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CVE-2020-5207
Request smuggling is possible in Ktor when both chunked TE and content length specified
Medium5.4EPSS 0.76%
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
In Ktor before 1.3.0, request smuggling is possible when running behind a proxy that doesn't handle Content-Length and Transfer-Encoding properly or doesn't handle \n as a headers separator.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.76% · top 44% of all CVEs (6 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.4.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavenio.ktor:ktor-client-cioGHSA-xrr9-rh8p-433v (opens in a new tab)
- Mavenio.ktor:ktor-server-cioGHSA-xrr9-rh8p-433v (opens in a new tab)
References (2)
- https://github.com/ktorio/ktor/security/advisories/GHSA-xrr9-rh8p-433v (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/ktorio/ktor/pull/1547 (opens in a new tab)x_refsource_MISCx_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)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-xrr9-rh8p-433v (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2020-5207)Record last updated .