UBUNTU-CVE-2026-42859

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Source
https://ubuntu.com/security/CVE-2026-42859
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42859.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-42859
Upstream
  • CVE-2026-42859
Published
2026-05-11T18:16:00Z
Modified
2026-05-27T19:15:22.673867211Z
Severity
  • 8.1 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Neat VNC is a VNC server library. Prior to 0.9.6, a pre-authentication stack buffer overflow exists in neatvnc in the RSA-AES security type handler. An unauthenticated remote attacker who can reach the VNC listening socket can send a crafted security type 5 (RSA-AES) or security type 129 (RSA-AES-256) handshake with an oversized client RSA public key, causing rsaaessend_challenge in src/auth/rsa-aes.c to overflow a 1024-byte on-stack buffer when encrypting the server challenge. This results in at least a denial of service via server crash. This vulnerability is fixed in 0.9.6.

References

Affected packages

Ubuntu:22.04:LTS / neatvnc

Package

Name
neatvnc
Purl
pkg:deb/ubuntu/neatvnc?arch=source&distro=jammy

Affected ranges

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

Affected versions

0.*
0.4.0+dfsg-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libneatvnc0",
            "binary_version": "0.4.0+dfsg-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42859.json"

Ubuntu:24.04:LTS / neatvnc

Package

Name
neatvnc
Purl
pkg:deb/ubuntu/neatvnc?arch=source&distro=noble

Affected ranges

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

Affected versions

0.*
0.6.0+dfsg-4build1
0.7.0+dfsg-1
0.7.1+dfsg-1
0.7.1+dfsg-2
0.7.1+dfsg-2build2
0.7.1+dfsg-2build3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libneatvnc0",
            "binary_version": "0.7.1+dfsg-2build3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42859.json"

Ubuntu:25.10 / neatvnc

Package

Name
neatvnc
Purl
pkg:deb/ubuntu/neatvnc?arch=source&distro=questing

Affected ranges

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

Affected versions

0.*
0.9.1+dfsg-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libneatvnc0",
            "binary_version": "0.9.1+dfsg-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42859.json"

Ubuntu:26.04:LTS / neatvnc

Package

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

Affected ranges

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

Affected versions

0.*
0.9.1+dfsg-1
0.9.1+dfsg-1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libneatvnc0",
            "binary_version": "0.9.1+dfsg-1build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42859.json"