Medium
Security advisory
QPDF 9.x through 9.1.1 and 10.x through 10.0.4 has a heap-based buffer overflow in Pl_ASCII85Decoder::write (called from Pl_AES_PDF::flush and Pl_AES_PDF::finish) when a certain downstream write fails.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-36978
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 12:45 UTC · Revision 1
Source evidence
QPDF 9.x through 9.1.1 and 10.x through 10.0.4 has a heap-based buffer overflow in Pl_ASCII85Decoder::write (called from Pl_AES_PDF::flush and Pl_AES_PDF::finish) when a certain downstream write fails.
osv:CVE-2021-36978
Complete source record
{
"id": "0f833e0b262d4abd17d33b4c5dc034aaa909b8c5724f151ca1ae079e3d2aea9e",
"url": "https://osv.dev/vulnerability/CVE-2021-36978",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-36978",
"summary": "QPDF 9.x through 9.1.1 and 10.x through 10.0.4 has a heap-based buffer overflow in Pl_ASCII85Decoder::write (called from Pl_AES_PDF::flush and Pl_AES_PDF::finish) when a certain downstream write fails.",
"evidence": "osv:CVE-2021-36978",
"products": [],
"severity": "medium",
"structured": {
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"aliases": [
"CVE-2021-36978"
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"metrics": [
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"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
}
],
"affected": [
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"repo": "https://github.com/qpdf/qpdf",
"type": "GIT",
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{
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"range": [
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},
{
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}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:qpdf_project:qpdf:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "10.0.0"
},
{
"last_affected": "10.0.4"
}
],
"source": "CPE_RANGE"
},
{
"range": [
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"fixed": "dc92574c10f3e2516ec6445b88c5d584f40df4e5"
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],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
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"release-qpdf-10.0.3",
"release-qpdf-10.0.2",
"release-qpdf-10.0.1",
"release-qpdf-10.0.0",
"release-qpdf-9.1.1",
"release-qpdf-9.1.0",
"release-qpdf-9.1.rc1",
"release-qpdf-9.0.2",
"release-qpdf-9.0.1",
"release-qpdf-9.0.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-36978.json",
"vanir_signatures": [
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"digest": {
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
"file": "libqpdf/Pl_ASCII85Decoder.cc",
"function": "Pl_ASCII85Decoder::flush"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
},
{
"id": "CVE-2021-36978-40dda416",
"digest": {
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
"file": "libqpdf/Pl_ASCIIHexDecoder.cc"
},
"deprecated": false,
"signature_type": "Line",
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{
"id": "CVE-2021-36978-63f64580",
"digest": {
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"function_hash": "187767804974098575998698531302435435782"
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
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"function": "Pl_Count::write"
},
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"signature_type": "Function",
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},
{
"id": "CVE-2021-36978-9c33a036",
"digest": {
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
"file": "libqpdf/Pl_AES_PDF.cc",
"function": "Pl_AES_PDF::flush"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
},
{
"id": "CVE-2021-36978-b6d83928",
"digest": {
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
"file": "libqpdf/Pl_ASCII85Decoder.cc"
},
"deprecated": false,
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},
{
"id": "CVE-2021-36978-c34a9232",
"digest": {
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
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{
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"digest": {
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
"file": "libqpdf/Pl_AES_PDF.cc"
},
"deprecated": false,
"signature_type": "Line",
"signature_version": "v1"
},
{
"id": "CVE-2021-36978-e8733a89",
"digest": {
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"function_hash": "154758842905624294376623863600796136195"
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"source": "https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5",
"target": {
"file": "libqpdf/Pl_ASCIIHexDecoder.cc",
"function": "Pl_ASCIIHexDecoder::flush"
},
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"signature_type": "Function",
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],
"vanir_signatures_modified": "2026-10-20T14:27:06Z"
}
}
],
"modified": "2026-10-20T14:27:06.501448072Z",
"provider": "osv",
"references": [
"https://lists.debian.org/debian-lts-announce/2023/08/msg00037.html",
"https://github.com/google/oss-fuzz-vulns/blob/main/vulns/qpdf/OSV-2020-2245.yaml",
"https://security.gentoo.org/glsa/202401-20",
"https://github.com/qpdf/qpdf/issues/492",
"https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28262",
"https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2021-36978",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 388996,
"published_at": "2021-07-20T07:15:08.03+00:00"
}