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/[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.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntupython3.14-venv (3.14.4-1ubuntu0.1) @ resolute2026-07-29ubuntu

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 21× 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 139 total refreshes for this CVE.

  1. 2026-07-30 16:28 UTCEPSS rescore
  2. 2026-07-30 01:30 UTCEPSS rescore
  3. 2026-07-29 06:14 UTCEG score recompute
  4. 2026-07-29 06:14 UTCVendor advisory
  5. 2026-07-29 06:14 UTCGHSA enrichment
  6. 2026-07-28 15:37 UTCEPSS rescore
  7. 2026-07-28 02:52 UTCEG score recompute
  8. 2026-07-28 02:52 UTCVendor advisory
  9. 2026-07-28 02:52 UTCGHSA enrichment
  10. 2026-07-27 14:14 UTCEPSS rescore
  11. 2026-07-27 10:04 UTCVendor advisory
  12. 2026-07-27 10:04 UTCGHSA enrichment
  13. 2026-07-26 21:40 UTCEG score recompute
  14. 2026-07-26 21:40 UTCVendor advisory
  15. 2026-07-26 21:40 UTCGHSA enrichment
  16. 2026-07-26 14:54 UTCEPSS rescore
  17. 2026-07-26 07:08 UTCEG score recompute
  18. 2026-07-26 07:08 UTCVendor advisory
  19. 2026-07-26 07:08 UTCGHSA enrichment
  20. 2026-07-25 14:18 UTCEPSS rescore
  21. 2026-07-24 14:18 UTCEPSS rescore
  22. 2026-07-23 14:18 UTCEPSS rescore
  23. 2026-07-23 03:23 UTCEG score recompute
  24. 2026-07-22 14:08 UTCEPSS rescore
  25. 2026-07-21 15:25 UTCEPSS rescore
Show 75 more
  1. 2026-07-21 15:25 UTCEPSS rescore
  2. 2026-07-20 17:08 UTCEPSS rescore
  3. 2026-07-19 02:29 UTCEPSS rescore
  4. 2026-07-18 10:04 UTCEPSS rescore
  5. 2026-07-16 17:03 UTCEPSS rescore
  6. 2026-07-16 09:39 UTCVendor advisory
  7. 2026-07-16 09:39 UTCGHSA enrichment
  8. 2026-07-15 20:32 UTCVendor advisory
  9. 2026-07-15 20:32 UTCGHSA enrichment
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 02:00 UTCEPSS rescore
  12. 2026-07-14 15:06 UTCVendor advisory
  13. 2026-07-14 15:06 UTCGHSA enrichment
  14. 2026-07-14 02:43 UTCVendor advisory
  15. 2026-07-14 02:43 UTCGHSA enrichment
  16. 2026-07-13 22:31 UTCEPSS rescore
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-12 11:28 UTCVendor advisory
  19. 2026-07-12 11:28 UTCGHSA enrichment
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 22:15 UTCVendor advisory
  22. 2026-07-11 22:15 UTCGHSA enrichment
  23. 2026-07-11 09:49 UTCVendor advisory
  24. 2026-07-11 09:49 UTCGHSA enrichment
  25. 2026-07-11 08:27 UTCEPSS rescore
  26. 2026-07-10 21:24 UTCVendor advisory
  27. 2026-07-10 21:24 UTCGHSA enrichment
  28. 2026-07-09 19:10 UTCEPSS rescore
  29. 2026-07-09 04:37 UTCVendor advisory
  30. 2026-07-09 04:37 UTCGHSA enrichment
  31. 2026-07-08 15:52 UTCVendor advisory
  32. 2026-07-08 15:52 UTCGHSA enrichment
  33. 2026-07-08 15:16 UTCEPSS rescore
  34. 2026-07-08 02:39 UTCVendor advisory
  35. 2026-07-08 02:39 UTCGHSA enrichment
  36. 2026-07-07 13:46 UTCEPSS rescore
  37. 2026-07-06 16:27 UTCEPSS rescore
  38. 2026-07-06 02:23 UTCEPSS rescore
  39. 2026-07-05 17:25 UTCGHSA enrichment
  40. 2026-07-05 03:27 UTCGHSA enrichment
  41. 2026-07-05 02:31 UTCEPSS rescore
  42. 2026-07-04 14:49 UTCGHSA enrichment
  43. 2026-07-04 06:31 UTCEPSS rescore
  44. 2026-07-03 21:49 UTCGHSA enrichment
  45. 2026-07-03 09:21 UTCGHSA enrichment
  46. 2026-07-02 19:47 UTCGHSA enrichment
  47. 2026-07-02 07:23 UTCGHSA enrichment
  48. 2026-07-01 18:53 UTCGHSA enrichment
  49. 2026-07-01 15:07 UTCEPSS rescore
  50. 2026-07-01 06:30 UTCGHSA enrichment
  51. 2026-06-30 23:22 UTCEPSS rescore
  52. 2026-06-30 16:24 UTCGHSA enrichment
  53. 2026-06-30 03:29 UTCGHSA enrichment
  54. 2026-06-29 15:05 UTCGHSA enrichment
  55. 2026-06-29 02:41 UTCGHSA enrichment
  56. 2026-06-28 14:18 UTCGHSA enrichment
  57. 2026-06-28 14:07 UTCEPSS rescore
  58. 2026-06-28 04:56 UTCEPSS rescore
  59. 2026-06-28 01:55 UTCGHSA enrichment
  60. 2026-06-27 13:32 UTCGHSA enrichment
  61. 2026-06-27 03:08 UTCEPSS rescore
  62. 2026-06-27 01:08 UTCGHSA enrichment
  63. 2026-06-26 12:45 UTCGHSA enrichment
  64. 2026-06-25 22:00 UTCGHSA enrichment
  65. 2026-06-25 13:50 UTCEPSS rescore
  66. 2026-06-25 09:37 UTCGHSA enrichment
  67. 2026-06-24 21:14 UTCGHSA enrichment
  68. 2026-06-24 14:05 UTCEPSS rescore
  69. 2026-06-24 04:58 UTCGHSA enrichment
  70. 2026-06-23 21:33 UTCEPSS rescore
  71. 2026-06-23 15:51 UTCGHSA enrichment
  72. 2026-06-23 02:13 UTCGHSA enrichment
  73. 2026-06-22 14:25 UTCEPSS rescore
  74. 2026-06-22 13:48 UTCGHSA enrichment
  75. 2026-06-21 19:47 UTCGHSA enrichment

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 65.7% 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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