Medium
pypy3 — security advisory
PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module's ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy's tracing garbage collector can free the parent's C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption.
- Products
- pypy3
- Affected versions
- 7.1.1+dfsg-1, 7.2.0+dfsg-1, 7.3.0+dfsg-1, 7.3.0+dfsg-1ubuntu2, 7.3.0+dfsg-1ubuntu3, 7.3.1+dfsg-4, 7.3.1+dfsg-4ubuntu0.1, 7.3.12+dfsg-1, 7.3.13+dfsg-1, 7.3.14+dfsg-1, 7.3.15+dfsg-1, 7.3.15+dfsg-1build2, 7.3.15+dfsg-1build3, 7.3.20+dfsg-3, 7.3.20+dfsg-4, 7.3.23+dfsg-1ubuntu1, 7.3.5+dfsg-2, 7.3.7+dfsg-1, 7.3.7+dfsg-4, 7.3.7+dfsg-5, 7.3.8+dfsg-2, 7.3.9+dfsg-1, 7.3.9+dfsg-1ubuntu0.1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-76875
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:18 UTC · Revision 1
Source evidence
PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module's ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy's tracing garbage collector can free the parent's C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption.
osv:UBUNTU-CVE-2026-76875
pypy3
Fixed versions: Not specified
pypy3
Fixed versions: Not specified
pypy3
Fixed versions: Not specified
pypy3
Fixed versions: Not specified
pypy3
Fixed versions: Not specified
Complete source record
{
"id": "f7dabe450c2233f6ca91f747dd233729b7754378d6b5bbd7f0d9cc00ba606f23",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-76875",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-76875",
"summary": "PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module's ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy's tracing garbage collector can free the parent's C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption.",
"evidence": "osv:UBUNTU-CVE-2026-76875",
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{
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{
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"evidence": "/affected/4/versions"
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{
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],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-76875",
"aliases": [
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"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
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{
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"affected": [
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"ecosystem": "Ubuntu:20.04:LTS"
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"versions": [
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"7.2.0+dfsg-1",
"7.3.0+dfsg-1",
"7.3.0+dfsg-1ubuntu2",
"7.3.0+dfsg-1ubuntu3",
"7.3.1+dfsg-4",
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"database_specific": {
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"ecosystem_specific": {
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},
{
"binary_name": "pypy3-lib",
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},
{
"binary_name": "pypy3-lib-testsuite",
"binary_version": "7.3.1+dfsg-4ubuntu0.1"
},
{
"binary_name": "pypy3-tk",
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}
]
}
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"package": {
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"purl": "pkg:deb/ubuntu/pypy3?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
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"7.3.9+dfsg-1",
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"database_specific": {
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],
"modified": "2026-10-17T13:01:07.047091091Z",
"provider": "osv",
"upstream": [
"CVE-2026-76875"
],
"references": [
"https://ubuntu.com/security/CVE-2026-76875",
"https://www.cve.org/CVERecord?id=CVE-2026-76875",
"https://doc.pypy.org/release-v8.0.0.html",
"https://github.com/pypy/pypy/releases/tag/release-pypy3.11-v8.0.0",
"https://github.com/pypy/pypy/releases/tag/release-pypy3.12-v8.0.0",
"https://www.vulncheck.com/advisories/pypy-pyexpat-externalentityparsercreate-use-after-free"
]
},
"related_cves": [
{
"value": "CVE-2026-76875",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 361010,
"published_at": "2026-09-29T13:17:00+00:00"
}