USN-7927-3

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Source
https://ubuntu.com/security/notices/USN-7927-3
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-7927-3.json
JSON Data
https://api.osv.dev/v1/vulns/USN-7927-3
Upstream
Related
Published
2026-01-13T14:36:44.125028Z
Modified
2026-01-20T16:46:18.493682Z
Summary
python-urllib3 regression
Details

USN-7927-1 fixed vulnerabilities in urllib3. The update for CVE-2025-66471 introduced a regression in urllib3 when decompressing zstd data. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Illia Volochii discovered that urllib3 did not limit the steps in a decompression chain. An attacker could possibly use this issue to cause urllib3 to use excessive resources, causing a denial of service. (CVE-2025-66418)

Rui Xi discovered that urllib3 incorrectly handled highly compressed data. An attacker could possibly use this issue to cause urllib3 to use excessive resources, causing a denial of service. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.04, and Ubuntu 25.10. (CVE-2025-66471)

For the brotli encoding, the fix for CVE-2025-66471 requires an additional security update in the brotli package.

References

Affected packages

Ubuntu:24.04:LTS / python-urllib3

Package

Name
python-urllib3
Purl
pkg:deb/ubuntu/python-urllib3@2.0.7-1ubuntu0.6?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.0.7-1ubuntu0.6

Affected versions

1.*

1.26.16-1
1.26.18-1

2.*

2.0.7-1
2.0.7-1ubuntu0.1
2.0.7-1ubuntu0.2
2.0.7-1ubuntu0.3
2.0.7-1ubuntu0.4
2.0.7-1ubuntu0.5

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "python3-urllib3",
            "binary_version": "2.0.7-1ubuntu0.6"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-7927-3.json"

cves_map

{
    "cves": [
        {
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ],
            "id": "CVE-2025-66471"
        }
    ],
    "ecosystem": "Ubuntu:24.04:LTS"
}

Ubuntu:25.10 / python-urllib3

Package

Name
python-urllib3
Purl
pkg:deb/ubuntu/python-urllib3@2.3.0-3ubuntu0.4?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
2.3.0-3ubuntu0.4

Affected versions

2.*

2.3.0-2
2.3.0-2ubuntu1
2.3.0-3
2.3.0-3ubuntu0.1
2.3.0-3ubuntu0.2
2.3.0-3ubuntu0.3

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "python3-urllib3",
            "binary_version": "2.3.0-3ubuntu0.4"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-7927-3.json"

cves_map

{
    "cves": [
        {
            "severity": [
                {
                    "type": "CVSS_V4",
                    "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H"
                },
                {
                    "type": "CVSS_V3",
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
                },
                {
                    "type": "Ubuntu",
                    "score": "medium"
                }
            ],
            "id": "CVE-2025-66471"
        }
    ],
    "ecosystem": "Ubuntu:25.10"
}