High
soupsieve — security advisory
Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.8.4, the CSS selector parser in soupsieve allocates unbounded memory when compiling large comma-separated selector lists, allowing an attacker who can supply a crafted selector string to soupsieve.compile() or Beautiful Soup .select() / .select_one() to allocate hundreds of megabytes of heap memory from a relatively small input and cause denial of service. This issue is fixed in version 2.8.4.
- Products
- soupsieve
- Affected versions
- 1.9.2+dfsg-2ubuntu1, 1.9.4+dfsg-1, 1.9.5+dfsg-1, 2.2.1-2, 2.3-1, 2.3.1-1, 2.4.1-2, 2.5-1, 2.7-2, 2.8.1-1, 2.8.3-1, 2.8.4-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-49476
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:44 UTC · Revision 1
Source evidence
Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.8.4, the CSS selector parser in soupsieve allocates unbounded memory when compiling large comma-separated selector lists, allowing an attacker who can supply a crafted selector string to soupsieve.compile() or Beautiful Soup .select() / .select_one() to allocate hundreds of megabytes of heap memory from a relatively small input and cause denial of service. This issue is fixed in version 2.8.4.
osv:UBUNTU-CVE-2026-49476
soupsieve
Fixed versions: Not specified
soupsieve
Fixed versions: Not specified
soupsieve
Fixed versions: Not specified
soupsieve
Fixed versions: Not specified
soupsieve
Fixed versions: Not specified
Complete source record
{
"id": "e52614417032e8682d384f496c6a69496a9506f5d3892bfd6afb7286d62ab4fb",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-49476",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-49476",
"summary": "Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.8.4, the CSS selector parser in soupsieve allocates unbounded memory when compiling large comma-separated selector lists, allowing an attacker who can supply a crafted selector string to soupsieve.compile() or Beautiful Soup .select() / .select_one() to allocate hundreds of megabytes of heap memory from a relatively small input and cause denial of service. This issue is fixed in version 2.8.4.",
"evidence": "osv:UBUNTU-CVE-2026-49476",
"products": [
{
"name": {
"value": "soupsieve",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.9.2+dfsg-2ubuntu1",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.4+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.9.5+dfsg-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "soupsieve",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.2.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.3.1-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "soupsieve",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.4.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.5-1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "soupsieve",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.8.3-1",
"evidence": "/affected/3/versions"
},
{
"value": "2.8.4-1",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "soupsieve",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.7-2",
"evidence": "/affected/4/versions"
},
{
"value": "2.8.1-1",
"evidence": "/affected/4/versions"
},
{
"value": "2.8.3-1",
"evidence": "/affected/4/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-49476",
"aliases": [
"UBUNTU-CVE-2026-49476"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "soupsieve",
"purl": "pkg:deb/ubuntu/soupsieve?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"1.9.2+dfsg-2ubuntu1",
"1.9.4+dfsg-1",
"1.9.5+dfsg-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49476.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python-soupsieve",
"binary_version": "1.9.5+dfsg-1"
},
{
"binary_name": "python3-soupsieve",
"binary_version": "1.9.5+dfsg-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "soupsieve",
"purl": "pkg:deb/ubuntu/soupsieve?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"2.2.1-2",
"2.3-1",
"2.3.1-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49476.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-soupsieve",
"binary_version": "2.3.1-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "soupsieve",
"purl": "pkg:deb/ubuntu/soupsieve?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"2.4.1-2",
"2.5-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49476.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-soupsieve",
"binary_version": "2.5-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "soupsieve",
"purl": "pkg:deb/ubuntu/soupsieve?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"2.8.3-1",
"2.8.4-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49476.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-soupsieve",
"binary_version": "2.8.4-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "soupsieve",
"purl": "pkg:deb/ubuntu/soupsieve?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"2.7-2",
"2.8.1-1",
"2.8.3-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49476.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "python3-soupsieve",
"binary_version": "2.8.3-1"
}
]
}
}
],
"modified": "2026-10-17T12:58:58.801290062Z",
"provider": "osv",
"upstream": [
"CVE-2026-49476"
],
"references": [
"https://ubuntu.com/security/CVE-2026-49476",
"https://www.cve.org/CVERecord?id=CVE-2026-49476",
"https://github.com/facelessuser/soupsieve/commit/28108ab805818c832d9568142a99844fd95a0d39",
"https://github.com/facelessuser/soupsieve/releases/tag/2.8.4",
"https://github.com/facelessuser/soupsieve/security/advisories/GHSA-2wc2-fm75-p42x"
]
},
"related_cves": [
{
"value": "CVE-2026-49476",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 359198,
"published_at": "2026-07-14T21:17:00+00:00"
}