CVE-2026-3298

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 78% 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, nvd
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.8Exploit: NoneExposed: 0

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

The method "sock_recvfrom_into()" of "asyncio.ProacterEventLoop" (Windows only) was missing a boundary check for the data buffer when using nbytes parameter. This allowed for an out-of-bounds buffer write if data was larger than the buffer size. Non-Windows platforms are not affected.

CVSS v3
8.8
EG Score
8.8(medium)
EPSS
29.6%
KEV
Not listed

Published

April 21, 2026

Last Modified

June 10, 2026

Advisory Details (6)

Auto-updated May 2, 2026
No patch confirmed yet.
generic

Mailman 3 [CVE-2026-3298] Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes - Security-announce - python.org

https://mail.python.org/archives/list/[email protected]/thread/KWTPIQBOOOUNQP7UFSLBI437NJDFLA3F/
generic

gh-148808: Add boundary check to asyncio.AbstractEventLoop.sock_recvf… by sethmlarson · Pull Request #148809 · python/cpython · GitHub

https://github.com/python/cpython/pull/148809
generic

asyncio.AbstractEventLoop.sock_recvfrom_into() on Windows doesn't check buffer length · Issue #148808 · python/cpython · GitHub

https://github.com/python/cpython/issues/148808
generic

[3.13] gh-148808: Add boundary check to asyncio.AbstractEventLoop.soc… · python/cpython@95633d2 · GitHub

https://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741
generic

[3.14] gh-148808: Add boundary check to asyncio.AbstractEventLoop.soc… · python/cpython@27522b7 · GitHub

https://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2
generic

gh-148808: Add boundary check to asyncio.AbstractEventLoop.sock_recvf… · python/cpython@1274766 · GitHub

https://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4d

Vendor Advisories for CVE-2026-3298(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 36× 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 122 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-3298?
CVE-2026-3298 is a high vulnerability published on April 21, 2026. The method "sockrecvfrominto()" of "asyncio.ProacterEventLoop" (Windows only) was missing a boundary check for the data buffer when using nbytes parameter. This allowed for an out-of-bounds buffer write if data was larger than the buffer size. Non-Windows platforms are not affected.
When was CVE-2026-3298 disclosed?
CVE-2026-3298 was first published in the National Vulnerability Database on April 21, 2026, with the most recent update on June 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-3298 actively exploited?
CVE-2026-3298 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-2026-3298?
CVE-2026-3298 has a CVSS v4.0 base score of 8.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-3298?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-3298, 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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