MediumFix available
botan — security advisory
The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.
- Products
- botan
- Affected versions
- Not specified
- Fixed versions
- 2.17.3-r3, 2.18.1-r3
- CVEs
- CVE-2021-40529
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:06 UTC · Revision 1
Source evidence
The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.
osv:ALPINE-CVE-2021-40529
botan
Fixed versions: 2.17.3-r3
botan
Fixed versions: 2.18.1-r3
botan
Fixed versions: 2.18.1-r3
botan
Fixed versions: 2.18.1-r3
botan
Fixed versions: 2.18.1-r3
botan
Fixed versions: 2.18.1-r3
botan
Fixed versions: 2.18.1-r3
botan
Fixed versions: 2.18.1-r3
Complete source record
{
"id": "a6438876f2205a0a841445c5113957b6c92e5dffd12c98dec2c1ac36faa2146a",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-40529",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ALPINE-CVE-2021-40529",
"summary": "The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.",
"evidence": "osv:ALPINE-CVE-2021-40529",
"products": [
{
"name": {
"value": "botan",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.17.3-r3",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "botan",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.18.1-r3",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "botan",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.18.1-r3",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "botan",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.18.1-r3",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "botan",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.18.1-r3",
"evidence": "/affected/4/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "botan",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.18.1-r3",
"evidence": "/affected/5/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "botan",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.18.1-r3",
"evidence": "/affected/6/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "botan",
"evidence": "/affected/7/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.18.1-r3",
"evidence": "/affected/7/ranges"
}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "ALPINE-CVE-2021-40529",
"aliases": [
"ALPINE-CVE-2021-40529"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.17.3-r3"
}
]
}
],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.14"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
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"events": [
{
"introduced": "0"
},
{
"fixed": "2.18.1-r3"
}
]
}
],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.15"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
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{
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{
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],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.16"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
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{
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],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.17"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
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}
]
}
],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.18"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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},
{
"fixed": "2.18.1-r3"
}
]
}
],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.19"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.18.1-r3"
}
]
}
],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.20"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.18.1-r3"
}
]
}
],
"package": {
"name": "botan",
"purl": "pkg:apk/alpine/botan?arch=source",
"ecosystem": "Alpine:v3.21"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-40529.json"
},
"ecosystem_specific": {}
}
],
"modified": "2026-10-23T17:17:56.211281723Z",
"provider": "osv",
"upstream": [
"CVE-2021-40529"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-40529"
]
},
"related_cves": [
{
"value": "CVE-2021-40529",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415546,
"published_at": "2021-09-06T19:15:07.63+00:00"
}