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.
CVE-2026-76875
MEDIUMPre-NVD 5.35.3—Trending — 4 sources updated this week
EchelonGraph scoreHIGH confidence
Score 5.3 from GitHub Security Advisory published 2026-09-29. A secondary CVSS source baseline 5.3; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.3Exploit: None knownExposed services: Not assessed
No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.
- CVSS v3
- 5.3
- EG Score
- 5.3MEDIUMhigh confidence
- EG Risk
- 39EG Risk 39/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity53% × 45%Exploitation0% × 40%Automatability100% × 15%CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix. - EPSS PROB
- 0.2%
- EPSS %ILE
- 13th
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).
No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
September 29, 2026
Last Modified
October 2, 2026
Advisory Details (2)
Auto-updated Sep 29, 2026No patch confirmed yet.
generic
PyPy pyexpat ExternalEntityParserCreate Use-After-Free | Advisories | VulnCheck
https://www.vulncheck.com/advisories/pypy-pyexpat-externalentityparsercreate-use-after-freegeneric
PyPy v8.0.0: release of python 2.7, 3.11, and 3.12 beta released 2026-09-19 — PyPy documentation
https://doc.pypy.org/release-v8.0.0.htmlVendor Advisories for CVE-2026-76875(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(3 across 3 ecosystems)
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| pypy3 | 7.3.11+dfsg-2 ... 8.0.0+dfsg-1 (31 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| pypy3 | 7.3.19+dfsg-2 ... 8.0.0+dfsg-1 (13 versions) |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| pypy3 | 7.3.19+dfsg-2 ... 7.3.23+dfsg-2 (12 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 19× in last 7d / 19× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-10-04 23:22 UTCEPSS rescore
- 2026-10-04 16:29 UTCGHSA enrichment
- 2026-10-03 14:53 UTCEG score recompute
- 2026-10-03 14:53 UTCGHSA enrichment
- 2026-10-03 14:26 UTCEPSS rescore
- 2026-10-02 13:18 UTCEG score recompute
- 2026-10-02 13:18 UTCGHSA enrichment
- 2026-10-02 12:22 UTCEG score recompute
- 2026-10-02 12:22 UTCGHSA enrichment
- 2026-10-02 01:51 UTCEG score recompute
- 2026-10-02 01:51 UTCGHSA enrichment
- 2026-10-01 19:50 UTCEPSS rescore
- 2026-10-01 00:14 UTCEG score recompute
- 2026-10-01 00:14 UTCGHSA enrichment
- 2026-09-29 22:00 UTCEG score recompute
- 2026-09-29 22:00 UTCGHSA enrichment
- 2026-09-29 13:38 UTCEG score recompute
- 2026-09-29 12:49 UTCEG score recompute
- 2026-09-29 12:48 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-76875?
CVE-2026-76875 is a medium vulnerability published on September 29, 2026. 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…
When was CVE-2026-76875 disclosed?
CVE-2026-76875 was first published on September 29, 2026, with the most recent update on October 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76875 actively exploited?
CVE-2026-76875 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-76875?
CVE-2026-76875 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-76875?
No fix for CVE-2026-76875 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-76875 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-76875
Is Your Infrastructure Affected by CVE-2026-76875?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.