HighFix available
py3-pygments — security advisory
In pygments 1.1+, fixed in 2.7.4, the lexers used to parse programming languages rely heavily on regular expressions. Some of the regular expressions have exponential or cubic worst-case complexity and are vulnerable to ReDoS. By crafting malicious input, an attacker can cause a denial of service.
- Products
- py3-pygments
- Affected versions
- Not specified
- Fixed versions
- 2.5.2-r1, 2.6.1-r1
- CVEs
- CVE-2021-27291
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 22:03 UTC · Revision 1
Source evidence
In pygments 1.1+, fixed in 2.7.4, the lexers used to parse programming languages rely heavily on regular expressions. Some of the regular expressions have exponential or cubic worst-case complexity and are vulnerable to ReDoS. By crafting malicious input, an attacker can cause a denial of service.
osv:ALPINE-CVE-2021-27291
py3-pygments
Fixed versions: 2.5.2-r1
py3-pygments
Fixed versions: 2.6.1-r1
Complete source record
{
"id": "08fd3c0adaf193e1756bd6fb0c64d478d41c5b94fb66f38472e02a4959576873",
"url": "https://osv.dev/vulnerability/ALPINE-CVE-2021-27291",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ALPINE-CVE-2021-27291",
"summary": "In pygments 1.1+, fixed in 2.7.4, the lexers used to parse programming languages rely heavily on regular expressions. Some of the regular expressions have exponential or cubic worst-case complexity and are vulnerable to ReDoS. By crafting malicious input, an attacker can cause a denial of service.",
"evidence": "osv:ALPINE-CVE-2021-27291",
"products": [
{
"name": {
"value": "py3-pygments",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.5.2-r1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "py3-pygments",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.6.1-r1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "ALPINE-CVE-2021-27291",
"aliases": [
"ALPINE-CVE-2021-27291"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.5.2-r1"
}
]
}
],
"package": {
"name": "py3-pygments",
"purl": "pkg:apk/alpine/py3-pygments?arch=source",
"ecosystem": "Alpine:v3.11"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-27291.json"
},
"ecosystem_specific": {}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
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"introduced": "0"
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{
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],
"package": {
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"purl": "pkg:apk/alpine/py3-pygments?arch=source",
"ecosystem": "Alpine:v3.12"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-27291.json"
},
"ecosystem_specific": {}
}
],
"modified": "2026-10-23T17:17:56.165537223Z",
"provider": "osv",
"upstream": [
"CVE-2021-27291"
],
"references": [
"https://security.alpinelinux.org/vuln/CVE-2021-27291"
]
},
"related_cves": [
{
"value": "CVE-2021-27291",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 415366,
"published_at": "2021-03-17T13:15:15.137+00:00"
}