FFmpeg 7.0 through 8.1.2, fixed in commit 4da9812, contains a heap out-of-bounds write vulnerability in the vfquirc filter that allows an attacker to corrupt heap memory by supplying a crafted PGS/SUP subtitle file with mismatched frame dimensions. Attackers can provide a subtitle file whose second presentation has larger dimensions than its first, causing avimagecopyplane() to copy data exceeding the initial allocation size into the undersized libquirc grayscale image buffer, resulting in heap corruption and process crash with potential for code execution.
{
"cwe_ids": [
"CWE-787"
],
"cna_assigner": "VulnCheck",
"unresolved_ranges": [
{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"introduced": "7.0"
},
{
"last_affected": "8.1.2"
}
]
},
{
"source": "CPE_FIELD",
"extracted_events": [
{
"introduced": "7.0"
},
{
"last_affected": "8.1.2"
}
]
},
{
"source": "DESCRIPTION",
"extracted_events": [
{
"introduced": "7.0"
},
{
"fixed": "8.1.2"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66041.json"
}