CVE-2026-105516
Description
A stack buffer overflow vulnerability was found in the 9P protocol implementation of NFS-Ganesha. The server does not validate the number of path components in a TWALK request against the protocol-defined limit of 16. An attacker can send a specially crafted TWALK message with thousands of path components, causing the server to write past the end of a fixed-size stack buffer during response construction. This can result in a crash or potentially remote code execution. The 9P protocol handler does not implement authentication, so the vulnerability is reachable without credentials by any client with network access to the 9P listener.
Statement
Red Hat's versions of nfs-ganesha do not compile the 9P protocol support, so this vulnerability does not affect any Red Hat products.
Mitigation
The 9P protocol support is not compiled in the versions of nfs-ganesha shipped in Red Hat products and Fedora. Only deployments that explicitly build nfs-ganesha with USE_9P=ON and expose a 9P listener are affected.
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 | 9.8 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Integrity,Confidentiality,Availability,Access Control
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands; Bypass Protection Mechanism
Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy.
Integrity,Confidentiality,Availability,Access Control,Other
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Other
When the consequence is arbitrary code execution, this can often be used to subvert any other security service.
Acknowledgements
Red Hat would like to thank Teddy Thobane (rootkiTed) for reporting this issue.
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