What is CVE-2026-12043?

CVE-2026-12043 is a high-severity vulnerability in AWS Aws-C-Http, classified under Double Free. CVSS score: 8.8/10. Published 2026-06-12.

How severe is CVE-2026-12043?

High severity. CVSS v3 base score is 8.8 out of 10.

Double Free in AWS Aws-C-Http

CVE-2026-12043

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.

Vulnerability class: Double Free

EPSS: 0.004 (28.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Aws Aws-c-http — versions 0.4.22

Weakness classification (CWE)

CWE-415 — Double Free

References

ff89ba41-3aa1-4d27-914a-91399e9639e5 (vendor-advisory)
ff89ba41-3aa1-4d27-914a-91399e9639e5 (patch)
ff89ba41-3aa1-4d27-914a-91399e9639e5 (third-party-advisory)

Frequently asked questions

What is CVE-2026-12043?: CVE-2026-12043 is a high-severity vulnerability in AWS Aws-C-Http, classified under Double Free. CVSS score: 8.8/10. Published 2026-06-12.
How severe is CVE-2026-12043?: High severity. CVSS v3 base score is 8.8 out of 10.