High
Security advisory
uBlock Origin before 1.36.2 and nMatrix before 4.4.9 support an arbitrary depth of parameter nesting for strict blocking, which allows crafted web sites to cause a denial of service (unbounded recursion that can trigger memory consumption and a loss of all blocking functionality).
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-36773
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 05:35 UTC · Revision 1
Source evidence
uBlock Origin before 1.36.2 and nMatrix before 4.4.9 support an arbitrary depth of parameter nesting for strict blocking, which allows crafted web sites to cause a denial of service (unbounded recursion that can trigger memory consumption and a loss of all blocking functionality).
osv:CVE-2021-36773
Complete source record
{
"id": "51d8dacea085aac885e6185e5017fde07a1da6eb1e5c6e892dd9d3061b27e04d",
"url": "https://osv.dev/vulnerability/CVE-2021-36773",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-36773",
"summary": "uBlock Origin before 1.36.2 and nMatrix before 4.4.9 support an arbitrary depth of parameter nesting for strict blocking, which allows crafted web sites to cause a denial of service (unbounded recursion that can trigger memory consumption and a loss of all blocking functionality).",
"evidence": "osv:CVE-2021-36773",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2021-36773",
"aliases": [
"CVE-2021-36773"
],
"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": [
{
"repo": "https://github.com/gorhill/ublock",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "8b5733a58d3acf9fb62815e14699c986bd1c2fdc"
}
],
"database_specific": {
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{
"cpe": "cpe:2.3:a:ublockorigin:ublock_origin:*:*:*:*:*:*:*:*",
"range": [
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{
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}
}
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}
},
{
"ranges": [
{
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},
{
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}
],
"database_specific": {
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{
"cpe": "cpe:2.3:a:umatrix_project:umatrix:*:*:*:*:*:*:*:*",
"range": [
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},
{
"fixed": "1.4.2"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
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],
"modified": "2026-10-24T10:30:30.837108961Z",
"provider": "osv",
"references": [
"https://lists.debian.org/debian-lts-announce/2022/06/msg00024.html",
"https://news.ycombinator.com/item?id=27833752",
"https://github.com/vtriolet/writings/blob/main/posts/2021/ublock_origin_and_umatrix_denial_of_service.adoc"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:a:sciruby:nmatrix:*:*:*:*:*:*:*:*"
],
"vendor_product": "sciruby:nmatrix",
"extracted_events": [
{
"range": [
{
"fixed": "4.4.9"
}
],
"source": "CPE_RANGE"
}
]
},
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2021-36773",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 432674,
"published_at": "2021-07-18T04:15:08.11+00:00"
}