CVE-2026-104020

Uncontrolled recursion in the Ion reader in Amazon Ion Python

State: Published
Severity: 8.7 High
Published: Oct 1, 2026
Updated: Oct 9, 2026
Reserved: Oct 1, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	AMZN
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	AMZN

Weaknesses

CWE-674 Uncontrolled recursion

Affected Products

Product	Versions
ion-pythonAmazon	before 0.15.0Affected

References

https://github.com/amazon-ion/ion-python/releases/tag/v0.15.0patch
https://aws.amazon.com/security/security-bulletins/2026-122-aws/vendor-advisory
https://github.com/amazon-ion/ion-python/security/advisories/GHSA-93q6-f8hx-vv7fthird-party-advisory

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