Medium
python-multidict — security advisory
Multidict is an implementation of a multidict data structure. From 6.7.0 until 6.9.1, the C extension's items-view reflected union operation, operand | d.items(), in multidict_itemsview_or2_impl and subtraction operation, d.items() - operand, in multidict_itemsview_sub1_impl fail to release new key-identity and value references returned for each operand element. Applications that perform these operations over attacker-influenced sequences can leak two strong references per element, and garbage collection cannot reclaim them, so repeated operations can cause unbounded process memory growth and denial of service. Forward union, intersection, non-tuple operand elements, and pure-Python builds are not affected by this reference leak. This issue is fixed in version 6.9.1.
- Products
- python-multidict
- Affected versions
- 3.1.3-1build1, 3.2.0-1, 3.3.2-1, 4.1.0-1, 4.5.2-1, 4.6.1-1, 4.7.3-1, 4.7.3-1build1, 5.1.0-1, 5.1.0-1build1, 5.1.0-1build2, 6.0.4-1.1, 6.0.4-1.1build1, 6.0.4-1build1, 6.4.3-1, 6.4.3-1build1, 6.4.3-1build2, 6.4.3-2
- Fixed versions
- Not specified
- CVEs
- CVE-2026-104874
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:40 UTC · Revision 1
Source evidence
Multidict is an implementation of a multidict data structure. From 6.7.0 until 6.9.1, the C extension's items-view reflected union operation, operand | d.items(), in multidict_itemsview_or2_impl and subtraction operation, d.items() - operand, in multidict_itemsview_sub1_impl fail to release new key-identity and value references returned for each operand element. Applications that perform these operations over attacker-influenced sequences can leak two strong references per element, and garbage collection cannot reclaim them, so repeated operations can cause unbounded process memory growth and denial of service. Forward union, intersection, non-tuple operand elements, and pure-Python builds are not affected by this reference leak. This issue is fixed in version 6.9.1.
osv:UBUNTU-CVE-2026-104874
python-multidict
Fixed versions: Not specified
python-multidict
Fixed versions: Not specified
python-multidict
Fixed versions: Not specified
python-multidict
Fixed versions: Not specified
python-multidict
Fixed versions: Not specified
python-multidict
Fixed versions: Not specified
Complete source record
{
"id": "807b171d83ee728ba81b23aefb2b4df45a05249a7bb7fd9f7462fc9fa2bce3ad",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-104874",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-104874",
"summary": "Multidict is an implementation of a multidict data structure. From 6.7.0 until 6.9.1, the C extension's items-view reflected union operation, operand | d.items(), in multidict_itemsview_or2_impl and subtraction operation, d.items() - operand, in multidict_itemsview_sub1_impl fail to release new key-identity and value references returned for each operand element. Applications that perform these operations over attacker-influenced sequences can leak two strong references per element, and garbage collection cannot reclaim them, so repeated operations can cause unbounded process memory growth and denial of service. Forward union, intersection, non-tuple operand elements, and pure-Python builds are not affected by this reference leak. This issue is fixed in version 6.9.1.",
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"aliases": [
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"modified": "2026-10-17T12:58:43.827715861Z",
"provider": "osv",
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"references": [
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"https://www.cve.org/CVERecord?id=CVE-2026-104874",
"https://github.com/aio-libs/multidict/security/advisories/GHSA-54p9-h82j-f925",
"https://github.com/aio-libs/multidict/commit/350b4a07bf8ff851b6d7544e81b1c748bdc74c40",
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"source_id": "core-osv",
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"published_at": "2026-10-02T21:16:00+00:00"
}