CVE-2026-105517
Description
A use-after-free vulnerability was found in the 9P protocol implementation of NFS-Ganesha. The server does not protect the lifetime of file identifier (FID) objects when processing concurrent requests. An attacker can race a write operation against a close operation on the same FID, causing one worker thread to free the FID and its associated data while another thread continues to use it. This allows attacker-controlled data to be written into freed heap memory, which 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 | 8.1 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | 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:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
Acknowledgements
Red Hat would like to thank Teddy Thobane (rootkiTed) for reporting this issue.
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