Medium
pypdf: Possible long runtimes/large memory usage when extracting XForm objects
Type: advisorySources: OSV
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-84311
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 01:03 UTC · Revision 1
Source evidence
pypdf: Possible long runtimes/large memory usage when extracting XForm objects
core-osv · Original sourcePublished 1 Sept 2026, 20:03 UTC
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.
osv:CVE-2026-84311
Complete source record
{
"id": "8e9bb8a4d975827aa1e9e36d509b22d9158e67d9b66973412f1f8a207a4220b0",
"url": "https://osv.dev/vulnerability/CVE-2026-84311",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "pypdf: Possible long runtimes/large memory usage when extracting XForm objects",
"summary": "pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.",
"evidence": "osv:CVE-2026-84311",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-84311",
"aliases": [
"CVE-2026-84311",
"GHSA-763m-79hh-57f2",
"PYSEC-2026-3911"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/py-pdf/pypdf",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "1bce7a755b4b24ef9d5f2b03f9882c115bec91f2"
},
{
"fixed": "d91ab705fd81ed1a9cec175c6958600dea1a4942"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "6.16.1"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "d91ab705fd81ed1a9cec175c6958600dea1a4942"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "1bce7a755b4b24ef9d5f2b03f9882c115bec91f2"
}
],
"source": "REFERENCES_TAG",
"original_tag": "6.16.1"
}
]
}
}
],
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-84311.json"
}
}
],
"modified": "2026-10-28T02:30:32.635146406Z",
"provider": "osv",
"references": [
"https://github.com/py-pdf/pypdf/releases/tag/6.16.1",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84311.json",
"https://github.com/py-pdf/pypdf/security/advisories/GHSA-763m-79hh-57f2",
"https://nvd.nist.gov/vuln/detail/CVE-2026-84311",
"https://github.com/py-pdf/pypdf/commit/d91ab705fd81ed1a9cec175c6958600dea1a4942",
"https://github.com/py-pdf/pypdf/pull/3966"
],
"provider_metadata": {
"cwe_ids": [
"CWE-834"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84311.json"
}
},
"related_cves": [
{
"value": "CVE-2026-84311",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 499392,
"published_at": "2026-09-01T20:03:13.421+00:00"
}