libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
{
"cna_assigner": "mitre",
"cwe_ids": [
"CWE-416"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/76xxx/CVE-2026-76957.json"
}{
"cpe": "cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "2.8.4"
}
],
"source": [
"AFFECTED_FIELD",
"CPE_RANGE"
]
}