CVE-2026-19643 Out-of-bounds read in the Base64 decoder in Amazon aws-sdk-cpp on signed-char platforms
A remote authenticated user can crash applications using the AWS C++ SDK by sending crafted Base64 input, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-19643?
CVE-2026-19643 is a medium-severity denial of service vulnerability in aws-sdk-cpp, published on 12 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An out-of-bounds read issue in the Base64 decoder in Amazon aws-sdk-cpp before 1.11.862, on some platforms, might allow a remote authenticated user to crash an application that processes crafted Base64-encoded input.
To remediate this issue, users should upgrade to version 1.11.862.
Weakness: CWE-125
Which versions are affected by CVE-2026-19643?
It affects 1 product.
Products include Amazon Aws Software Development Kit.
How do I fix CVE-2026-19643?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-19643 being exploited?
There is no known exploitation of CVE-2026-19643 in the wild and no public exploit code.
Other vulnerabilities in aws-sdk-cpp
- CVE-2018-19981 Information disclosure in n/a
- CVE-2026-19642 Out-of-bounds write in the Base64 decoder in Amazon aws-sdk-cpp
- CVE-2023-51651 Potential URI resolution path traversal in the AWS SDK for PHP
- CVE-2022-4725 AWS SDK XML Parser XpathUtils.java XpathUtils server-side request forgery
- CVE-2022-2582 Exposure of unencrypted plaintext hash in github.com/aws/aws-sdk-go
Sources
Also known as GHSA-mxm9-xpf9-x66x.