CVE-2026-19643Network attack vector

Authenticated application crash via Base64 decode-table overread

Published Aug 12, 2026 · Updated Aug 12, 2026

Out-of-bounds read in Amazon Web Services' AWS SDK for C++ before 1.11.862 allows remote authenticated users to crash decoding applications. On signed-char platforms, crafted Base64 input causes the core library's decoder to index outside its decode table. Reachability requires a generated service client to decode attacker-controlled input; impact is confined to the decoding process, with no reported data disclosure or modification.

CVSS severity6.0
Medium
EPSS probability0.34%
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 read in Amazon Web Services' AWS SDK for C++ before 1.11.862 allows remote authenticated users to crash decoding applications. On signed-char platforms, crafted Base64 input causes the core library's decoder to index outside its decode table. Reachability requires a generated service client to decode attacker-controlled input; impact is confined to the decoding process, with no reported data disclosure or modification.

The record

CVE
CVE-2026-19643
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
Amazon Web Services
Product
AWS SDK for C++
Classifications
CWE-125, CAPEC-540, T1499.004
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:N/VA:H/SC:N/SI:N/SA:N
5.3Amazon Web ServicesCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
CAPEC-540Overread Buffers
T1499.004Application or System Exploitation

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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