CVE-2026-104020

High

Description

Uncontrolled recursion in the Ion reader in Amazon Ion Python before 0.15.0 might allow a remote unauthenticated actor to crash the application using the library, resulting in a denial of service, via a crafted, deeply nested Ion value. To remediate this issue, users should upgrade to version 0.15.0 or later.

SeverityHigh

CVSS7.5

Exploit probability—

ProductAmazon Ion-python

PublishedOct 1, 2026

First seenOct 1, 2026

Weakness typeCWE-674CWE-674

How to fix

Update

Amazon ion-python0.15.0 or later

Patches

github.com/amazon-ion/ion-python/releases/tag/v0.15.0

Vendor advisories

aws.amazon.com/security/security-bulletins/2026-122-aws/

Affected products

Product	Affected versions	Fixed in
Amazon ion-python	v < 0.15.0	0.15.0

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.