Undertow is Vulnerable to HTTP Request/Response Smuggling
A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request smuggling attacks, potentially bypassing security controls and accessing unauthorized resources.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | io.undertow:undertow-parent | <= 2.3.23.Final | no fix |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N- Weakness (CWE)
CWE-444- Platform
- Java / Kotlin (Maven)
- Package
io.undertow:undertow-parent- Disclosed
- 27.03.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-8v4x-mgvp-p658 - CC BY 4.0
Vulnerability history: io.undertow:undertow-parent
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 4
- First → latest
- 09.2023 03.2026
- Without a fix
- 3
- Exploited in attacks
- 0
Severity breakdown
- High 4
Disclosures per year
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 3
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Undertow is Vulnerable to HTTP Request/Response Smuggling this entry
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