CVE-2026-64194
Description
A flaw was found in Net::DNS. A remote attacker can exploit this vulnerability by sending a specially crafted DNS packet with deep compression pointer chains. This can cause excessive recursion in the Net::DNS::DomainName::decode function, leading to stack exhaustion and a Denial of Service (DoS) for any application processing untrusted DNS data.
Statement
Contrary to the CVE description, this issue does not easily trigger an application crash via stack memory exhaustion, as the Perl interpreter handles this recursion without doing recursive function calls and by saving recursion state on the heap. It is possible to trigger a crash via out-of-(heap)-memory condition. Due to the input size being restricted via DNS protocol packet limits, such condition is only triggerable for processes with low heap memory limits. For processes with higher or no heap memory limit, this issue triggers transient limit memory usage spike.
Based on the impact described above, Red Hat has rated this issue as having Moderate security impact.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | 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 | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/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:H
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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