Critical
mpack — security advisory
An integer overflow vulnerability exists in the MPack Node API in MPack 1.1.1 on 32-bit platforms. When parsing a specially crafted MessagePack array32 or map32 object with an excessively large element count, the page allocation size calculation in mpack_tree_parse_children() can overflow size_t and produce an undersized allocation. Subsequent parsing writes mpack_node_data_t records beyond the allocated heap buffer, resulting in heap-buffer-overflow, memory corruption, and denial of service.
- Products
- mpack
- Affected versions
- 1.6-17, 1.6-18, 1.6-19, 1.6-19build1, 1.6-8, 1.6-8.1, 1.6-8.2
- Fixed versions
- Not specified
- CVEs
- CVE-2026-88351
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:30 UTC · Revision 1
Source evidence
An integer overflow vulnerability exists in the MPack Node API in MPack 1.1.1 on 32-bit platforms. When parsing a specially crafted MessagePack array32 or map32 object with an excessively large element count, the page allocation size calculation in mpack_tree_parse_children() can overflow size_t and produce an undersized allocation. Subsequent parsing writes mpack_node_data_t records beyond the allocated heap buffer, resulting in heap-buffer-overflow, memory corruption, and denial of service.
osv:UBUNTU-CVE-2026-88351
mpack
Fixed versions: Not specified
mpack
Fixed versions: Not specified
mpack
Fixed versions: Not specified
mpack
Fixed versions: Not specified
mpack
Fixed versions: Not specified
mpack
Fixed versions: Not specified
mpack
Fixed versions: Not specified
Complete source record
{
"id": "235f343b34591f02f8dedac661b61064c31072ae2bd435c345ff05cd022795b1",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-88351",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-88351",
"summary": "An integer overflow vulnerability exists in the MPack Node API in MPack 1.1.1 on 32-bit platforms. When parsing a specially crafted MessagePack array32 or map32 object with an excessively large element count, the page allocation size calculation in mpack_tree_parse_children() can overflow size_t and produce an undersized allocation. Subsequent parsing writes mpack_node_data_t records beyond the allocated heap buffer, resulting in heap-buffer-overflow, memory corruption, and denial of service.",
"evidence": "osv:UBUNTU-CVE-2026-88351",
"products": [
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"evidence": "/affected/0/package/name"
},
"prerequisites": [],
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"affected_versions": [
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{
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]
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"severity": "critical",
"structured": {
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"aliases": [
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"metrics": [
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"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
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"database_specific": {
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],
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],
"modified": "2026-10-17T13:01:15.731820855Z",
"provider": "osv",
"upstream": [
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],
"references": [
"https://ubuntu.com/security/CVE-2026-88351",
"https://www.cve.org/CVERecord?id=CVE-2026-88351"
]
},
"related_cves": [
{
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"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 361414,
"published_at": "2026-09-24T15:17:00+00:00"
}