CVE-2026-12043
Bulletin ID: 2026-043-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 06/12/2026 11:45 AM PDT Description: AWS Common Runtime aws-c-http is a HTTP client library used by AWS SDKs for handling http requests to AWS services. We identified CVE-2026-12043, an issue where improper handling of HPACK dynamic table size updates in the AWS Common Runtime aws-c-http library might allow a remote 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. Impacted versions: aws-c-http >= 0.4.22 AND <= 0.10.15 Exposed in following sdk versions: - aws-sdk-cpp >= 1.11.41, <= 1.11.814 - aws-sdk-java-v2 >= 2.44.27, <= 2.44.14 Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.
CSIRTS triage
- What
- Improper handling of HPACK dynamic table size updates may lead to memory corruption and potential arbitrary code execution.
- Who is affected
- Users of aws-c-http within the specified version range.
- Urgency
- Remediation is urgent due to the potential for remote code execution.
- Action
- Update aws-c-http to a version outside the affected range.
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Exploitation outlook
- Low exploitation risk0.35% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 27% of all EPSS-scored CVEs.
Advisory coverage (1)
- unknownCVE-2026-12043 - Heap double-free in AWS Common Runtime aws-c-httpaws · 2026-06-12
External references
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