USN-8115-1 (UBUNTU-CVE-2026-27448)
Vulnerability from osv_ubuntu – Published: 2026-03-23 13:08 – Updated: 2026-06-30 15:54 – Source website
VLAI
Summary
pyopenssl vulnerabilities
Details
It was discovered that pyOpenSSL incorrectly handled exceptions in the tlsext_servername callback. This could result in connections being accepted after an exception, contrary to expectations. (CVE-2026-27448)
It was discovered that pyOpenSSL incorrectly handled the DTLS cookie generation callback. If a callback provided cookie values greater than 256 bytes, an attacker could use this issue to cause pyOpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 25.10. (CVE-2026-27459)
References
| URL | Type | |
|---|---|---|
{
"affected": [
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-27448",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U",
"type": "CVSS_V4"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "low",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:22.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "python3-openssl",
"binary_version": "21.0.0-1ubuntu0.1"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "pyopenssl",
"purl": "pkg:deb/ubuntu/pyopenssl@21.0.0-1ubuntu0.1?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "21.0.0-1ubuntu0.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"20.0.1-1",
"21.0.0-1"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-27448",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U",
"type": "CVSS_V4"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "low",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-27459",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U",
"type": "CVSS_V4"
},
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:24.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "python3-openssl",
"binary_version": "23.2.0-1ubuntu0.1"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "pyopenssl",
"purl": "pkg:deb/ubuntu/pyopenssl@23.2.0-1ubuntu0.1?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "23.2.0-1ubuntu0.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"23.0.0-1",
"23.2.0-1"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-27448",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U",
"type": "CVSS_V4"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "low",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-27459",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U",
"type": "CVSS_V4"
},
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:25.10"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "python3-openssl",
"binary_version": "25.0.0-1ubuntu0.1"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "pyopenssl",
"purl": "pkg:deb/ubuntu/pyopenssl@25.0.0-1ubuntu0.1?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "25.0.0-1ubuntu0.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"25.0.0-1"
]
}
],
"aliases": [],
"details": "It was discovered that pyOpenSSL incorrectly handled exceptions in the\ntlsext_servername callback. This could result in connections being\naccepted after an exception, contrary to expectations. (CVE-2026-27448)\n\nIt was discovered that pyOpenSSL incorrectly handled the DTLS cookie\ngeneration callback. If a callback provided cookie values greater than 256\nbytes, an attacker could use this issue to cause pyOpenSSL to crash,\nresulting in a denial of service, or possibly execute arbitrary code. This\nissue only affected Ubuntu 24.04 LTS and Ubuntu 25.10. (CVE-2026-27459)",
"id": "USN-8115-1",
"modified": "2026-06-30T15:54:54Z",
"published": "2026-03-23T13:08:05Z",
"references": [
{
"type": "ADVISORY",
"url": "https://ubuntu.com/security/notices/USN-8115-1"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-27448"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-27459"
}
],
"related": [],
"schema_version": "1.7.0",
"summary": "pyopenssl vulnerabilities",
"upstream": [
"UBUNTU-CVE-2026-27448",
"UBUNTU-CVE-2026-27459"
]
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
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They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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