UBUNTU-CVE-2026-123611

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Source
https://ubuntu.com/security/CVE-2026-123611
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123611.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-123611
Upstream
Published
2026-11-09T00:00:00Z
Modified
2026-11-10T02:50:22Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

rustls before 0.23.46 contains a key exchange downgrade vulnerability that allows network attackers to poison the per-server-name key-exchange group record via an unauthenticated ServerHello. Attackers can answer one connection with a ServerHello selecting X25519, causing later ClientHellos to send only classical shares and lose post-quantum confidentiality.

References

Affected packages

Ubuntu:24.04:LTS / rust-rustls

Package

Name
rust-rustls
Purl
pkg:deb/ubuntu/rust-rustls?arch=source&distro=noble

Affected ranges

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

Affected versions

0.*
0.21.6-3
0.21.7-1
0.21.9-1
0.21.10-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "librust-rustls-dev",
            "binary_version": "0.21.10-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123611.json"

Ubuntu:26.10 / rust-rustls

Package

Name
rust-rustls
Purl
pkg:deb/ubuntu/rust-rustls?arch=source&distro=stonking

Affected ranges

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

Affected versions

0.*
0.23.36+ds-1
0.23.41+ds-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "librust-rustls-dev",
            "binary_version": "0.23.41+ds-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123611.json"

Ubuntu:26.04:LTS / rust-rustls

Package

Name
rust-rustls
Purl
pkg:deb/ubuntu/rust-rustls?arch=source&distro=resolute

Affected ranges

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

Affected versions

0.*
0.23.26+ds-1
0.23.33+ds-3build2
0.23.35+ds-1
0.23.35+ds-1build1
0.23.36+ds-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "librust-rustls-dev",
            "binary_version": "0.23.36+ds-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123611.json"