HTTP Smuggling via Transfer-Encoding Header in Puma
Published May 22, 2020 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
HTTP Smuggling via Transfer-Encoding Header in Puma
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
By using an invalid transfer-encoding header, an attacker could [smuggle an HTTP response.](https://portswigger.net/web-security/request-smuggling)
Potential impact
By using an invalid transfer-encoding header, an attacker could smuggle an HTTP response. Originally reported by @ZeddYu, who has our thanks for the detailed report.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- Security advisory ↗
- Source repository ↗
- Patch commit ↗
- openSUSE-SU-2020:0990 ↗
- openSUSE-SU-2020:1001 ↗
- FEDORA-2020-fe354f24e8 ↗
- [debian-lts-announce] 20201007 [SECURITY] [DLA 2398-1] puma security update ↗
Record history
Published May 22, 2020 · Last refreshed Nov 3, 2026