CVE-2026-39373
Description
A flaw was found in JWCrypto, a Python library for JSON Web Key (JWK), JSON Web Signature (JWS), and JSON Web Encryption (JWE) specifications. An unauthenticated attacker can exploit this vulnerability by sending specially crafted JWE tokens that use ZIP compression. While the input token size is limited, the decompressed output size is not validated, allowing an attacker to cause excessive memory consumption. This can lead to memory exhaustion on affected systems, resulting in a Denial of Service (DoS).
Statement
This is an Important denial of service vulnerability in JWCrypto, a Python library used in Red Hat products such as Red Hat Ansible Automation Platform and Red Hat Enterprise Linux. An unauthenticated attacker can send specially crafted JWE tokens with ZIP compression, leading to excessive memory consumption and potential system exhaustion. This can result in a denial of service on affected systems.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 5.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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