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 66% 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 — 4 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 0

A fix is available — apply it.

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)
EG Risk
37(Track)
EG Risk 37/100SSVC: Track

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 computed
Severity82% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

June 8, 2026

Last Modified

July 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/security-announce@python.org/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.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntupython3.14-venv (3.14.4-1ubuntu0.1) @ resolute2026-07-28ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 20× in last 7d / 76× 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 133 total refreshes for this CVE.

  1. 2026-07-28 02:52 UTCEG score recompute
  2. 2026-07-28 02:52 UTCVendor advisory
  3. 2026-07-28 02:52 UTCGHSA enrichment
  4. 2026-07-27 14:14 UTCEPSS rescore
  5. 2026-07-27 10:04 UTCVendor advisory
  6. 2026-07-27 10:04 UTCGHSA enrichment
  7. 2026-07-26 21:40 UTCEG score recompute
  8. 2026-07-26 21:40 UTCVendor advisory
  9. 2026-07-26 21:40 UTCGHSA enrichment
  10. 2026-07-26 14:54 UTCEPSS rescore
  11. 2026-07-26 07:08 UTCEG score recompute
  12. 2026-07-26 07:08 UTCVendor advisory
  13. 2026-07-26 07:08 UTCGHSA enrichment
  14. 2026-07-25 14:18 UTCEPSS rescore
  15. 2026-07-24 14:18 UTCEPSS rescore
  16. 2026-07-23 14:18 UTCEPSS rescore
  17. 2026-07-23 03:23 UTCEG score recompute
  18. 2026-07-22 14:08 UTCEPSS rescore
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  21. 2026-07-20 17:08 UTCEPSS rescore
  22. 2026-07-19 02:29 UTCEPSS rescore
  23. 2026-07-18 10:04 UTCEPSS rescore
  24. 2026-07-16 17:03 UTCEPSS rescore
  25. 2026-07-16 09:39 UTCVendor advisory
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  1. 2026-07-16 09:39 UTCGHSA enrichment
  2. 2026-07-15 20:32 UTCVendor advisory
  3. 2026-07-15 20:32 UTCGHSA enrichment
  4. 2026-07-15 16:57 UTCEPSS rescore
  5. 2026-07-15 02:00 UTCEPSS rescore
  6. 2026-07-14 15:06 UTCVendor advisory
  7. 2026-07-14 15:06 UTCGHSA enrichment
  8. 2026-07-14 02:43 UTCVendor advisory
  9. 2026-07-14 02:43 UTCGHSA enrichment
  10. 2026-07-13 22:31 UTCEPSS rescore
  11. 2026-07-13 06:13 UTCEPSS rescore
  12. 2026-07-12 11:28 UTCVendor advisory
  13. 2026-07-12 11:28 UTCGHSA enrichment
  14. 2026-07-12 05:46 UTCEPSS rescore
  15. 2026-07-11 22:15 UTCVendor advisory
  16. 2026-07-11 22:15 UTCGHSA enrichment
  17. 2026-07-11 09:49 UTCVendor advisory
  18. 2026-07-11 09:49 UTCGHSA enrichment
  19. 2026-07-11 08:27 UTCEPSS rescore
  20. 2026-07-10 21:24 UTCVendor advisory
  21. 2026-07-10 21:24 UTCGHSA enrichment
  22. 2026-07-09 19:10 UTCEPSS rescore
  23. 2026-07-09 04:37 UTCVendor advisory
  24. 2026-07-09 04:37 UTCGHSA enrichment
  25. 2026-07-08 15:52 UTCVendor advisory
  26. 2026-07-08 15:52 UTCGHSA enrichment
  27. 2026-07-08 15:16 UTCEPSS rescore
  28. 2026-07-08 02:39 UTCVendor advisory
  29. 2026-07-08 02:39 UTCGHSA enrichment
  30. 2026-07-07 13:46 UTCEPSS rescore
  31. 2026-07-06 16:27 UTCEPSS rescore
  32. 2026-07-06 02:23 UTCEPSS rescore
  33. 2026-07-05 17:25 UTCGHSA enrichment
  34. 2026-07-05 03:27 UTCGHSA enrichment
  35. 2026-07-05 02:31 UTCEPSS rescore
  36. 2026-07-04 14:49 UTCGHSA enrichment
  37. 2026-07-04 06:31 UTCEPSS rescore
  38. 2026-07-03 21:49 UTCGHSA enrichment
  39. 2026-07-03 09:21 UTCGHSA enrichment
  40. 2026-07-02 19:47 UTCGHSA enrichment
  41. 2026-07-02 07:23 UTCGHSA enrichment
  42. 2026-07-01 18:53 UTCGHSA enrichment
  43. 2026-07-01 15:07 UTCEPSS rescore
  44. 2026-07-01 06:30 UTCGHSA enrichment
  45. 2026-06-30 23:22 UTCEPSS rescore
  46. 2026-06-30 16:24 UTCGHSA enrichment
  47. 2026-06-30 03:29 UTCGHSA enrichment
  48. 2026-06-29 15:05 UTCGHSA enrichment
  49. 2026-06-29 02:41 UTCGHSA enrichment
  50. 2026-06-28 14:18 UTCGHSA enrichment
  51. 2026-06-28 14:07 UTCEPSS rescore
  52. 2026-06-28 04:56 UTCEPSS rescore
  53. 2026-06-28 01:55 UTCGHSA enrichment
  54. 2026-06-27 13:32 UTCGHSA enrichment
  55. 2026-06-27 03:08 UTCEPSS rescore
  56. 2026-06-27 01:08 UTCGHSA enrichment
  57. 2026-06-26 12:45 UTCGHSA enrichment
  58. 2026-06-25 22:00 UTCGHSA enrichment
  59. 2026-06-25 13:50 UTCEPSS rescore
  60. 2026-06-25 09:37 UTCGHSA enrichment
  61. 2026-06-24 21:14 UTCGHSA enrichment
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  63. 2026-06-24 04:58 UTCGHSA enrichment
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  65. 2026-06-23 15:51 UTCGHSA enrichment
  66. 2026-06-23 02:13 UTCGHSA enrichment
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  71. 2026-06-21 02:01 UTCGHSA enrichment
  72. 2026-06-21 01:59 UTCEPSS rescore
  73. 2026-06-20 11:39 UTCGHSA enrichment
  74. 2026-06-19 23:13 UTCGHSA enrichment
  75. 2026-06-19 19:26 UTCEPSS rescore

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 July 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 0% probability of exploitation in the next 30 days, which ranks it in the top 65.8% of all scored CVEs.
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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