pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48156.json",
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-834"
]
}{
"source": [
"AFFECTED_FIELD",
"CPE_RANGE",
"REFERENCES"
],
"cpe": "cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "6.12.0"
}
]
}