CVE-2026-12043

HIGHPre-NVD 8.88.8
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 73% 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
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.

Improper handling of HPACK dynamic table size updates in the AWS Common Runtime aws-c-http library might allow a remote threat actor operating a server to cause memory corruption on a connecting client application, potentially leading to arbitrary code execution, via a crafted sequence of HTTP/2 HEADERS frames.

To remediate this issue, users should upgrade to aws-c-http version 0.11.0.

CVSS v3
8.8
EG Score
8.8(medium)
EPSS
27.1%
KEV
Not listed

Published

June 12, 2026

Last Modified

June 16, 2026

Advisory Details (2)

Auto-updated Jun 12, 2026
Patch available. Sources: github_release.
github_release Patch Available

Fix rounding error in hpack resizing

Patch available: awslabs/aws-c-http v0.11.0

https://github.com/awslabs/aws-c-http/releases/tag/v0.11.0
generic

CVE-2026-12043 - Heap double-free in AWS Common Runtime aws-c-http

https://aws.amazon.com/security/security-bulletins/2026-043-aws/

Vendor Advisories for CVE-2026-12043(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 21× in last 7d / 80× 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.

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

Frequently asked(5)

What is CVE-2026-12043?
CVE-2026-12043 is a high vulnerability published on June 12, 2026. Improper handling of HPACK dynamic table size updates in the AWS Common Runtime aws-c-http library might allow a remote threat actor operating a server to cause memory corruption on a connecting client application, potentially leading to arbitrary code execution, via a crafted sequence of HTTP/2…
When was CVE-2026-12043 disclosed?
CVE-2026-12043 was first published in the National Vulnerability Database on June 12, 2026, with the most recent update on June 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-12043 actively exploited?
CVE-2026-12043 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 27.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-12043?
CVE-2026-12043 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-12043?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-12043, 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.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-12043

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