High
libmongocrypt — security advisory
Improper handling of an unexpected value size in the decryption path of a client-side encryption library can cause a failed internal check that terminates the process using the library. A party able to place a suitably formed encrypted value where an application will decrypt it, or able to control the responses the application receives, may cause that application to stop running.
- Products
- libmongocrypt
- Affected versions
- 1.13.2-1, 1.17.0-1, 1.19.0-1, 1.19.1-1, 1.2.1-1, 1.2.2-1, 1.20.0-1, 1.20.1-1build1, 1.20.2-1, 1.3.0-1, 1.3.0-1ubuntu1, 1.7.2-1, 1.8.2-1, 1.8.4-1, 1.8.4-1build2, 1.8.4-1build3
- Fixed versions
- Not specified
- CVEs
- CVE-2026-84971
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:23 UTC · Revision 1
Source evidence
Improper handling of an unexpected value size in the decryption path of a client-side encryption library can cause a failed internal check that terminates the process using the library. A party able to place a suitably formed encrypted value where an application will decrypt it, or able to control the responses the application receives, may cause that application to stop running.
osv:UBUNTU-CVE-2026-84971
libmongocrypt
Fixed versions: Not specified
libmongocrypt
Fixed versions: Not specified
libmongocrypt
Fixed versions: Not specified
libmongocrypt
Fixed versions: Not specified
Complete source record
{
"id": "a1e8dde962ff96ba5c956040a57cc36dad4d9d3a8ecb8f9a6f0ca2429673116c",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-84971",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-84971",
"summary": "Improper handling of an unexpected value size in the decryption path of a client-side encryption library can cause a failed internal check that terminates the process using the library. A party able to place a suitably formed encrypted value where an application will decrypt it, or able to control the responses the application receives, may cause that application to stop running.",
"evidence": "osv:UBUNTU-CVE-2026-84971",
"products": [
{
"name": {
"value": "libmongocrypt",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.2.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.2.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.3.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.3.0-1ubuntu1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "libmongocrypt",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.7.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.8.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.8.4-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.8.4-1build2",
"evidence": "/affected/1/versions"
},
{
"value": "1.8.4-1build3",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "libmongocrypt",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.17.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.19.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.20.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.20.1-1build1",
"evidence": "/affected/2/versions"
},
{
"value": "1.20.2-1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "libmongocrypt",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.13.2-1",
"evidence": "/affected/3/versions"
},
{
"value": "1.17.0-1",
"evidence": "/affected/3/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-84971",
"aliases": [
"UBUNTU-CVE-2026-84971"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libmongocrypt",
"purl": "pkg:deb/ubuntu/libmongocrypt?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"1.2.1-1",
"1.2.2-1",
"1.3.0-1",
"1.3.0-1ubuntu1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84971.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libmongocrypt0",
"binary_version": "1.3.0-1ubuntu1"
}
]
}
},
{
"ranges": [
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],
"package": {
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"purl": "pkg:deb/ubuntu/libmongocrypt?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
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"1.8.2-1",
"1.8.4-1",
"1.8.4-1build2",
"1.8.4-1build3"
],
"database_specific": {
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},
"ecosystem_specific": {
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{
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"binary_version": "1.8.4-1build3"
}
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}
},
{
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"type": "ECOSYSTEM",
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],
"package": {
"name": "libmongocrypt",
"purl": "pkg:deb/ubuntu/libmongocrypt?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"1.17.0-1",
"1.19.0-1",
"1.19.1-1",
"1.20.0-1",
"1.20.1-1build1",
"1.20.2-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84971.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libmongocrypt0",
"binary_version": "1.20.2-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libmongocrypt",
"purl": "pkg:deb/ubuntu/libmongocrypt?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"1.13.2-1",
"1.17.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84971.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libmongocrypt0",
"binary_version": "1.17.0-1"
}
]
}
}
],
"modified": "2026-10-17T13:01:13.022223517Z",
"provider": "osv",
"upstream": [
"CVE-2026-84971"
],
"references": [
"https://ubuntu.com/security/CVE-2026-84971",
"https://www.cve.org/CVERecord?id=CVE-2026-84971",
"https://jira.mongodb.org/browse/MONGOCRYPT-971"
]
},
"related_cves": [
{
"value": "CVE-2026-84971",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 361270,
"published_at": "2026-09-03T15:17:00+00:00"
}