High · CVSS 7.7CVE-2026-5190

AWS C Event Stream Streaming Decoder Stack Buffer OverflowCVE-2026-5190

Answer in brief

CVE-2026-5190 records a High severity (CVSS 7.7) vulnerability in AWS C Event Stream Streaming Decoder Stack Buffer Overflow. The current sources do not mark it as known exploited. The current feed maps AWS/aws-c-event-stream (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Mar 31, 2026Updated Oct 20, 2026Source checked Oct 20, 2026First seen by HOL Oct 20, 2026Material review Oct 20, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 7.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps AWS/aws-c-event-stream (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
AWS/aws-c-event-streamgeneric	>=0 <0.6.0	0.6.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for AWS/aws-c-event-stream.
Review the reported fix. Update AWS/aws-c-event-stream to 0.6.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Mar 31, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 20, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 20, 2026

Sources and claim methodology

Upstream source description

Out-of-bounds write in the streaming decoder component in aws-c-event-stream before 0.6.0 might allow a third party operating a server to cause memory corruption leading to arbitrary code execution on a client application that processes crafted event-stream messages. To remediate this issue, users should upgrade to version 0.6.0 or later.

Quoted source text, attributed separately from HOL analysis.