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Linux KernelOperating system · Linux

CVE-2010-2521

HIGH · 10.0 CVSS v2.0 Published 2010-09-07
Fix available
A fix is available. Upgrade to after 2.6.34 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Multiple buffer overflows in fs/nfsd/nfs4xdr.c in the XDR implementation in the NFS server in the Linux kernel before 2.6.34-rc6 allow remote attackers to cause a denial of service (panic) or possibly execute arbitrary code via a crafted NFSv4 compound WRITE request, related to the read_buf and nfsd4_decode_compound functions.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Buffer overflow vulnerability in the Linux kernel's NFSv4 server XDR implementation (fs/nfsd/nfs4xdr.c). The read_buf and nfsd4_decode_compound functions fail to properly bounds-check when processing NFSv4 compound WRITE requests, allowing remote attackers to trigger a kernel panic or potentially achieve arbitrary code execution.

MitigationUpgrade Linux kernel to version 2.6.34-rc6 or later, which contains the bounds-checking fix for the vulnerable XDR functions.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:<= 2.6.34= 2.6.0= 2.6.1= 2.6.2= 2.6.3= 2.6.4= 2.6.5= 2.6.6= 2.6.7= 2.6.8= 2.6.8.1= 2.6.9

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed kernel version
    Run `uname -r` or `cat /proc/version` to obtain the running kernel version
    Affected if The kernel version is 2.6.34 or earlier (2.6.0 through 2.6.9, or any version <= 2.6.34)
  2. Verify NFS kernel module is loaded
    Run `lsmod | grep nfsd` to check if the nfsd kernel module is loaded
    Affected if The nfsd module is loaded, indicating NFS server functionality is present
  3. Check if NFS server service is running
    Run `service nfs status` or `systemctl status nfs-server` (or check for rpc.nfsd processes with `ps aux | grep nfsd`)
    Affected if The NFS server daemon is actively running
  4. Identify NFS exports configured
    Examine `/etc/exports` and run `exportfs -v` to list NFS export paths
    Affected if NFS exports are defined, meaning the server is configured to serve filesystems
  5. Confirm NFSv4 protocol in use
    Check `/etc/exports` for 'fsid=0' or 'v4' options, or inspect `/proc/fs/nfsd/versions` for NFSv4 support
    Affected if NFSv4 protocol support is enabled (the vulnerability specifically affects NFSv4 compound request processing)

A system is affected if it runs a kernel version <= 2.6.34 and has the NFSv4 server (nfsd) module loaded and configured to serve NFSv4 exports.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 2.6.34
Interim mitigation

Upgrade Linux kernel to version 2.6.34-rc6 or later, which contains the bounds-checking fix for the vulnerable XDR functions.

Recommended fix High confidence

Linux Kernel 2.6.34-rc6 or later stable release (e.g., 2.6.34 stable)

  1. Identify the current kernel version using 'uname -r' or 'cat /proc/version'
  2. Backup critical data and configuration files before proceeding
  3. Check package manager availability (yum, apt, dnf, zypper depending on distribution)
  4. Update package lists: 'yum check-update' (RHEL/CentOS) or 'apt-get update' (Debian/Ubuntu)
  5. Install the new kernel package: 'yum install kernel-2.6.34' or 'apt-get install linux-image-2.6.34'
  6. Update bootloader configuration (GRUB) to ensure the new kernel is bootable
  7. Reboot the system to load the new kernel: 'reboot'
  8. After reboot, verify the new kernel is running: 'uname -r'
Caveat Kernel upgrades may require rebuilding third-party kernel modules; ensure driver compatibility with the new kernel version before upgrading in production environments

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2010-2521 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data