CVE-2024-53216
Description
A flaw was found in the Linux kernel's Network File System daemon (nfsd). A local user can trigger a use-after-free condition when export cache entries are prematurely released during read operations. This issue may lead to memory corruption, potentially causing a system crash and resulting in a Denial of Service (DoS).
Mitigation
To mitigate this issue on systems that do not require NFS server capabilities, prevent the nfsd kernel module from loading by adding a configuration file to /etc/modprobe.d/:
# echo "install nfsd /bin/true" > /etc/modprobe.d/nfsd.conf
If the NFS server service is currently running, stop and disable it:
# systemctl stop nfs-server
# systemctl disable nfs-server
If the nfsd module is already loaded in memory, attempt to unload it or restart the system:
# modprobe -r nfsd
Warning: Blacklisting nfsd disables NFS export functionality on the host, though NFS client operations remain unaffected. Unloading the module or restarting the system will disrupt active NFS exports and existing client sessions.
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 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/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.
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