CVE-2023-53360
📋 TL;DR
A double-free vulnerability in the Linux kernel's NFSv4.2 READ_PLUS implementation could cause kernel crashes (oops) when processing certain network file system operations. This affects systems using NFSv4.2 with the READ_PLUS feature enabled. The vulnerability occurs due to improper scratch buffer management during multiple read requests.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially causing data loss or service disruption.
Likely Case
Kernel oops (crash) when processing NFSv4.2 READ_PLUS operations with hole segments, resulting in temporary service disruption until system recovery.
If Mitigated
Minimal impact if NFSv4.2 READ_PLUS is not used or systems are patched.
🎯 Exploit Status
Exploitation requires ability to trigger NFSv4.2 READ_PLUS operations with specific conditions. More likely to be triggered accidentally than maliciously.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 303a78052091c81e9003915c521fdca1c7e117af, a2f4cb206bd94b3f4a7bb05fcdce9525283b5681, adac9f0ddd2b291c7ce41f549fdb27a13616cff5, ae5d5672f1db711e91db6f52df5cb16ecd8f5692
Vendor Advisory: https://git.kernel.org/stable/c/303a78052091c81e9003915c521fdca1c7e117af
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable NFSv4.2 READ_PLUS
allDisable the READ_PLUS feature in NFSv4.2 configuration to prevent triggering the vulnerable code path.
# On NFS server: add 'no_read_plus' to export options
# On NFS client: mount with '-o no_read_plus' option
🧯 If You Can't Patch
- Disable NFSv4.2 entirely and use NFSv4.1 or NFSv3 if possible
- Implement network segmentation to isolate NFS traffic and limit potential impact
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if NFSv4.2 with READ_PLUS is enabled. Examine /proc/version and NFS configuration files.Check Version:
uname -rVerify Fix Applied:
Verify kernel version contains the fix commits. Check that NFS operations no longer cause kernel crashes when using READ_PLUS.📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages in /var/log/kern.log or dmesg
- NFS error messages related to READ_PLUS operations
- System crash/panic logs
Network Indicators:
- Increased NFS error responses
- Unusual NFSv4.2 READ_PLUS traffic patterns
SIEM Query:
source="kernel" AND ("Oops" OR "kernel panic") AND ("NFS" OR "READ_PLUS")