UBUNTU-CVE-2026-19879

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Source
https://ubuntu.com/security/CVE-2026-19879
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19879.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-19879
Upstream
  • CVE-2026-19879
Published
2026-08-17T00:00:00Z
Modified
2026-08-17T12:30:32.331411432Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

A flaw was found in Undertow, an HTTP server, within its HTTP response header writing path. The writeString() method performs a silent narrowing cast from 16-bit Unicode characters to 8-bit bytes when writing HTTP response header values. A remote attacker can exploit this by supplying specific Unicode characters in user-controlled input that an application places into response headers. This can lead to the truncation of these characters into ASCII control characters or special symbols, potentially resulting in limited integrity impact or information disclosure if the application does not properly sanitize user input.

References

Affected packages

Ubuntu:26.04:LTS
undertow

Package

Name
undertow
Purl
pkg:deb/ubuntu/undertow?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.3.18-2
2.3.20-1
2.3.20-1ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libundertow-java",
            "binary_version": "2.3.20-1ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19879.json"
Ubuntu:Pro:16.04:LTS
undertow

Package

Name
undertow
Purl
pkg:deb/ubuntu/undertow?arch=source&distro=esm-apps%2Fxenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.3.4-1
1.3.5-1
1.3.7-1
1.3.11-1
1.3.16-1
1.3.16-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libundertow-java",
            "binary_version": "1.3.16-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19879.json"
Ubuntu:Pro:18.04:LTS
undertow

Package

Name
undertow
Purl
pkg:deb/ubuntu/undertow?arch=source&distro=esm-apps%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.4.20-1
1.4.21-1
1.4.22-1
1.4.23-1
1.4.23-2build1
1.4.23-3
1.4.23-3ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libundertow-java",
            "binary_version": "1.4.23-3ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19879.json"
Ubuntu:Pro:20.04:LTS
undertow

Package

Name
undertow
Purl
pkg:deb/ubuntu/undertow?arch=source&distro=esm-apps%2Ffocal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.0.23-1
2.0.27-1
2.0.28-1
2.0.29-1
2.0.29-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libundertow-java",
            "binary_version": "2.0.29-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19879.json"
Ubuntu:Pro:22.04:LTS
undertow

Package

Name
undertow
Purl
pkg:deb/ubuntu/undertow?arch=source&distro=esm-apps%2Fjammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.2.8-1
2.2.12-1
2.2.13-1
2.2.14-1
2.2.16-1
2.2.16-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libundertow-java",
            "binary_version": "2.2.16-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19879.json"
Ubuntu:Pro:24.04:LTS
undertow

Package

Name
undertow
Purl
pkg:deb/ubuntu/undertow?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.3.8-2
2.3.8-2ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libundertow-java",
            "binary_version": "2.3.8-2ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-19879.json"