pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-835"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84309.json"
}{
"extracted_events": [
{
"cpe": "cpe:2.3:a:py-pdf:pypdf:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "6.16.0"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "c9ba557d565d57c53a0b3a0be06c0a4c29b0559b"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "6.16.0",
"range": [
{
"fixed": "2b60c99973df8d7f959cd46658604d881be3de3a"
}
],
"source": "REFERENCES_TAG"
}
]
}