🛡️ CVE-2021-3859 on Debian — undertow

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

A flaw was found in Undertow that tripped the client-side invocation timeout with certain calls made over HTTP2. This flaw allows an attacker to carry out denial of service attacks.

Distribution advisory

This page covers CVE-2021-3859 as tracked by Debian, for the package undertow. The fix is available in version 2.2.16-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

DEBIAN-CVE-2021-3859 is classified as CWE-214: Invocation of Process Using Visible Sensitive Information. A process is invoked with sensitive command-line arguments, environment variables, or other elements that can be seen by other processes on the operating system.

Affected software

DEBIAN-CVE-2021-3859 is recorded against 1 package.

  • undertow (fixed in 2.2.16-1)

Timeline and source

Published on 26 August 2022 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2021-3859 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2022-08-26
Updated 2026-08-20
Modified 2026-08-04
Fix URL N/A

Affected Packages

Software From version Fixed in
undertow — 2.2.16-1

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DEBIAN-CVE-2021-3859 is rated CVSS 8.0 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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