CVE-2026-92822
Description
A flaw was found in libmodulemd. When parsing module metadata, the xmd field is converted into nested GVariant values through recursive YAML mapping and sequence helpers without a recursion-depth or node-count limit. An attacker who can supply crafted modulemd YAML with deeply nested xmd content can cause stack exhaustion or excessive resource consumption, resulting in a denial of service.
Statement
This Moderate flaw is an availability-only denial of service in libmodulemd. Exploitation requires a consumer to parse attacker-controlled modulemd YAML containing a deeply nested xmd structure. Environments that only ingest trusted module metadata are not practically exposed. Confidentiality and integrity impact were not established.
Mitigation
Avoid parsing untrusted modulemd documents that may contain attacker-controlled xmd data. If such input must be accepted, reject unusually deep or large xmd structures before handing them to libmodulemd, and isolate parsing in a process with strict stack, CPU, and memory limits.
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 | 6.2 | N/A | 6.2 |
| Attack Vector | Local | N/A | Local |
| 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 | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/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)
Resources including CPU, memory, and stack memory could be rapidly consumed or exhausted, eventually leading to an exit or crash.
Confidentiality
Technical Impact: Read Application Data
In some cases, an application's interpreter might kill a process or thread that appears to be consuming too many resources, such as with PHP's memory_limit setting. When the interpreter kills the process/thread, it might report an error containing detailed information such as the application's installation path.
Acknowledgements
Red Hat would like to thank AISLE Research for reporting this issue.
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