CVE-2026-19642Network attack vector

Process crash via heap-buffer overrun

Published Aug 12, 2026 · Updated Aug 12, 2026

Out-of-bounds write in the Base64 decoder in AWS SDK for C++ before 1.11.862 allows remote authenticated users to crash an application. The core library decoder writes past the end of its heap-allocated output buffer when generated service clients pass certain crafted Base64 input. A reachable decode path and low privileges are required; impact is confined to the decoding process, where memory can be corrupted, but remote code execution has not been demonstrated.

CVSS severity6.0
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in the Base64 decoder in AWS SDK for C++ before 1.11.862 allows remote authenticated users to crash an application. The core library decoder writes past the end of its heap-allocated output buffer when generated service clients pass certain crafted Base64 input. A reachable decode path and low privileges are required; impact is confined to the decoding process, where memory can be corrupted, but remote code execution has not been demonstrated.

The record

CVE
CVE-2026-19642
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
Amazon Web Services
Product
AWS SDK for C++
Classifications
CWE-787, CAPEC-100, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=1.11.861

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Amazon Web Services · AWS SDK for C++version=0 <=1.11.861

Published CVSS scores

6.0Amazon Web ServicesCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
5.9Amazon Web ServicesCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CAPEC-100Overflow Buffers
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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