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Medium

HTTP Request Smuggling in Undertow

  • Disclosed: 30.04.2021
  • Updated: 11.10.2026 11:22

A flaw was found in Undertow in versions before 2.1.1.Final, regarding the processing of invalid HTTP requests with large chunk sizes. This flaw allows an attacker to take advantage of HTTP request smuggling.

Affected software

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PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) io.undertow:undertow-core < 2.1.1.Final 2.1.1.Final

References

CVSS score 6.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness (CWE)
CWE-444
Platform
Java / Kotlin (Maven)
Package
io.undertow:undertow-core
Disclosed
30.04.2021
Updated
11.10.2026 11:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-cccf-7xw3-p2vr - CC BY 4.0

Vulnerability history: io.undertow:undertow-core

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.

All (39) in the archive
Total entries
39
First → latest
10.2018 03.2026
Without a fix
1
Exploited in attacks
0

Severity breakdown

  • Critical 4
  • High 19
  • Medium 16

Disclosures per year

Severity:
  1. HTTP Request Smuggling in Undertow this entry
    Medium · 6.5 CVE-2020-10719 < 2.1.1.Final 2.1.1.Final
  2. Undertow Servlets Vulnerable to Remote DoS via OutOfMemoryError when Passed Large Parameter Names
    High · 7.5 CVE-2024-4027 < 2.2.39.Final, >= 2.4.0.Alpha1, < 2.4.0.Beta1, >= 2.3.0.Alpha1, < 2.3.21.Final 2.2.39.Final, 2.4.0.Beta1, 2.3.21.Final
  3. Undertow HTTP server core doesn't properly validate the Host header in incoming HTTP requests
    Critical · 9.6 CVE-2025-12543 >= 2.3.0.Alpha1, < 2.3.21.Final, < 2.2.39.Final, = 2.4.0.Alpha1 2.3.21.Final, 2.2.39.Final
  4. Undertow OutOfMemory when parsing form data encoding with application/x-www-form-urlencoded
    High · 7.5 CVE-2024-3884 < 2.2.39.Final, >= 2.4.0.Alpha1, < 2.4.0.Beta1, >= 2.3.0.Alpha1, < 2.3.21.Final 2.2.39.Final, 2.4.0.Beta1, 2.3.21.Final
  5. Undertow MadeYouReset HTTP/2 DDoS Vulnerability
    High · 7.5 CVE-2025-9784 < 2.2.38.Final, >= 2.3.0.Alpha1, < 2.3.20.Final 2.2.38.Final, 2.3.20.Final
  6. Undertow incorrectly parses cookies
    High · 7.4 CVE-2023-4639 >= 2.3.0.Alpha1, < 2.3.11.Final, < 2.2.30.Final 2.3.11.Final, 2.2.30.Final
  7. Undertow vulnerable to Race Condition
    High · 7.5 CVE-2024-7885 < 2.2.36.Final, >= 2.3.0.Alpha1, < 2.3.17.Final 2.2.36.Final, 2.3.17.Final
  8. Undertow Denial of Service vulnerability
    High · 7.5 CVE-2024-5971 >= 2.3.0.Alpha1, < 2.3.15.Final, < 2.2.34.Final 2.3.15.Final, 2.2.34.Final
  9. Undertow's url-encoded request path information can be broken on ajp-listener
    High · 7.5 CVE-2024-6162 >= 2.3.0.Alpha1, < 2.3.14.Final, < 2.2.33.Final 2.3.14.Final, 2.2.33.Final
  10. Undertow Uncontrolled Resource Consumption Vulnerability
    High · 7.5 CVE-2024-1635 >= 2.3.0.Final, < 2.3.12.Final, < 2.2.31.Final 2.3.12.Final, 2.2.31.Final
  11. Undertow denial of service vulnerability
    High · 7.5 CVE-2023-1108 >= 2.3.0, < 2.3.5.Final, < 2.2.24.Final 2.3.5.Final, 2.2.24.Final
  12. Undertow client not checking server identity presented by server certificate in https connections
    Critical · 9.8 CVE-2022-4492 >= 2.3.0, < 2.3.5.Final, < 2.2.24.Final 2.3.5.Final, 2.2.24.Final
  13. Undertow vulnerable to Dos via Large AJP request
    High · 7.5 CVE-2022-2053 < 2.2.19.Final, >= 2.3.0.Alpha1, < 2.3.0.Alpha2 2.2.19.Final, 2.3.0.Alpha2
  14. Undertow vulnerable to Denial of Service (DoS) attacks
    High · 7.5 CVE-2021-3859 < 2.2.15 2.2.15
  15. Undertow vulnerable to memory exhaustion due to buffer leak
    High · 7.5 CVE-2021-3690 < 2.0.40, >= 2.2.0, < 2.2.10 2.0.40, 2.2.10
  16. Undertow Uncontrolled Resource Consumption
    High · 7.5 CVE-2021-3629 < 2.0.40.Final, >= 2.1.0, < 2.2.11.Final 2.0.40.Final, 2.2.11.Final
  17. Improper Authorization in Undertoe
    High · 8.6 CVE-2020-1745 < 2.0.30 2.0.30
  18. Improper Input Validation in Undertow
    High · 8.1 CVE-2020-1757 < 2.1.0 2.1.0
  19. Undertow vulnerable to Uncontrolled Resource Consumption
    High · 7.5 CVE-2019-14888 < 2.0.29.Final 2.0.29.Final
  20. Undertow Request Smuggling vulnerability
    High · 7.5 CVE-2017-12165 < 1.3.31, >= 1.4.0, < 1.4.17, >= 2.0.0.Alpha1, < 2.0.0.Beta1 1.3.31, 1.4.17, 2.0.0.Beta1
  21. Denial of service in Undertow
    High · 7.5 CVE-2020-27782 >= 2.1.0, < 2.1.5, < 2.0.33 2.1.5, 2.0.33
Show more (3) Showing 21 of 24

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