In libxml2 before 2.15.4, xmlDictAddQString in dict.c has an integer overflow and resultant heap-based buffer overflow.
{
"cwe_ids": [
"CWE-190"
],
"cna_assigner": "mitre",
"unresolved_ranges": [
{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"fixed": "2.15.4"
}
]
},
{
"source": "CPE_FIELD",
"extracted_events": [
{
"fixed": "2.15.4"
}
]
},
{
"source": "DESCRIPTION",
"extracted_events": [
{
"introduced": "libxml2"
},
{
"fixed": "2.15.4"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86138.json"
}[
{
"target": {
"file": "dict.c",
"function": "xmlDictAddQString"
},
"deprecated": false,
"id": "CVE-2026-86138-898a92aa",
"signature_version": "v1",
"digest": {
"function_hash": "213641069474404204084264476307831275105",
"length": 1173.0
},
"signature_type": "Function",
"source": "https://github.com/gnome/libxml2/commit/a4cba4b5b5a8c42e155ed42d2d2a44955465a2e4"
},
{
"target": {
"file": "dict.c"
},
"deprecated": false,
"id": "CVE-2026-86138-8ce6b94c",
"signature_version": "v1",
"digest": {
"line_hashes": [
"22705769131571515735424788648057189731",
"127538958424616110891429405908535635948",
"127237673969423964965216091459784473112",
"261222054137941156001661941752090969459",
"76272764599133584965117187399028073755",
"211226901711502655471136293220249554424",
"314189873811252664231640710837597585269"
],
"threshold": 0.9
},
"signature_type": "Line",
"source": "https://github.com/gnome/libxml2/commit/a4cba4b5b5a8c42e155ed42d2d2a44955465a2e4"
}
]
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-86138.json"
"2026-09-06T08:01:51Z"