HighFix available
mediawiki, 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
- mediawiki, pygments
- Affected versions
- Not specified
- Fixed versions
- 1:1.35.2-1, 2.7.1+dfsg-2.1
- CVEs
- CVE-2021-27291
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 00:33 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:DEBIAN-CVE-2021-27291
mediawiki
Fixed versions: 1:1.35.2-1
mediawiki
Fixed versions: 1:1.35.2-1
mediawiki
Fixed versions: 1:1.35.2-1
pygments
Fixed versions: 2.7.1+dfsg-2.1
pygments
Fixed versions: 2.7.1+dfsg-2.1
pygments
Fixed versions: 2.7.1+dfsg-2.1
Complete source record
{
"id": "18df8790fbe69a03d3bef2fe2214a6871e9eef8d777849b80fc115582c83eab8",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-27291",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-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:DEBIAN-CVE-2021-27291",
"products": [
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"name": {
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"evidence": "/affected/0/package/name"
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"evidence": "/affected/0/ranges"
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{
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"severity": "high",
"structured": {
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"aliases": [
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"metrics": [
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"affected": [
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},
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},
{
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],
"package": {
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"purl": "pkg:deb/debian/pygments?arch=source&distro=forky",
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},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-27291.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:03:25.982336938Z",
"provider": "osv",
"upstream": [
"CVE-2021-27291"
],
"references": [
"https://security-tracker.debian.org/tracker/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": 421491,
"published_at": "2021-03-17T13:15:15.137+00:00"
}