CVE-2026-9669

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 70% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.2Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

bz2.BZ2Decompressor objects could be reused after a decompression error. If an application caught the resulting OSError and retried with the same decompressor, crafted input could cause the decompressor to resume from an invalid internal state and perform out-of-bounds writes to a stack buffer. This could crash the process when processing untrusted data.

CVSS v3
8.2
EG Score
8.2(medium)
EPSS
29.6%
KEV
Not listed

Published

June 8, 2026

Last Modified

June 23, 2026

Advisory Details (4)

Auto-updated Jun 9, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
generic

oss-security - [CVE-2026-9669] CPython: bz2.BZ2Decompressor reuse after error can cause a stack buffer overflow

http://www.openwall.com/lists/oss-security/2026/06/08/17
generic

Mailman 3 [CVE-2026-9669] bz2.BZ2Decompressor reuse after error can cause a stack buffer overflow - Security-announce - python.org

https://mail.python.org/archives/list/[email protected]/thread/DBJZETMGUIFK7DVUWMOXHD3Z6IX2QPSX/
github_pr

gh-150599: Prevent bz2 decompressor reuse after errors

Fix merged in python/cpython PR #150600 on 2026-06-07 — awaiting tagged release

https://github.com/python/cpython/pull/150600
generic

Stack buffer overflow in bz2 when reusing BZ2Decompressor after error · Issue #150599 · python/cpython · GitHub

https://github.com/python/cpython/issues/150599

Vendor Advisories for CVE-2026-9669(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 26× in last 7d / 127× 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.

Showing the most recent 100 of 127 total refreshes for this CVE.

  1. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 02:23 UTCEPSS rescore
  3. 2026-07-05 17:25 UTCEG score recompute
  4. 2026-07-05 17:25 UTCGHSA enrichment
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  21. 2026-07-01 15:07 UTCEPSS rescore
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  1. 2026-06-30 16:24 UTCGHSA enrichment
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  9. 2026-06-28 14:18 UTCGHSA enrichment
  10. 2026-06-28 14:07 UTCEPSS rescore
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  13. 2026-06-28 01:55 UTCGHSA enrichment
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  18. 2026-06-27 01:08 UTCGHSA enrichment
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  46. 2026-06-20 11:39 UTCGHSA enrichment
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  49. 2026-06-19 19:26 UTCEPSS rescore
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  67. 2026-06-15 17:49 UTCEPSS rescore
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  72. 2026-06-14 23:18 UTCEPSS rescore
  73. 2026-06-14 14:47 UTCEG score recompute
  74. 2026-06-14 14:47 UTCGHSA enrichment
  75. 2026-06-14 02:22 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-9669?
CVE-2026-9669 is a high vulnerability published on June 8, 2026. bz2.BZ2Decompressor objects could be reused after a decompression error. If an application caught the resulting OSError and retried with the same decompressor, crafted input could cause the decompressor to resume from an invalid internal state and perform out-of-bounds writes to a stack buffer.…
When was CVE-2026-9669 disclosed?
CVE-2026-9669 was first published in the National Vulnerability Database on June 8, 2026, with the most recent update on June 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-9669 actively exploited?
CVE-2026-9669 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 29.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-9669?
CVE-2026-9669 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-9669?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-9669, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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