Is CVE-2026-12043 in the CISA KEV catalog?

No. CVE-2026-12043 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-12043?

CVE-2026-12043 has a CVSS v3 base score of 8.8 (HIGH).

What is the EPSS score for CVE-2026-12043?

CVE-2026-12043 has an EPSS score of 0.35% (27th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-12043

HIGH

8.8

CVSS v3

NVD

Description

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.

CWE-415

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploit Intelligence

0.35%probability of exploitation in 30 days

27thpercentile

Low risk: more likely to be exploited than 27% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-16.