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Linux KernelOperating system · Linux

CVE-2009-1527

MEDIUM · 6.9 CVSS v2.0 Published 2009-05-05
Fix available
A fix is available. Upgrade to after 2.6.29 or later.
See remediation →
74/100
Remediation priority · Elevated
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
Race condition in the ptrace_attach function in kernel/ptrace.c in the Linux kernel before 2.6.30-rc4 allows local users to gain privileges via a PTRACE_ATTACH ptrace call during an exec system call that is launching a setuid application, related to locking an incorrect cred_exec_mutex object.

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

Race condition in Linux kernel's ptrace_attach function allows local users to gain privileges by issuing a PTRACE_ATTACH call during an exec system call that is launching a setuid application. The vulnerability stems from locking an incorrect cred_exec_mutex object, creating a window where a malicious local user can attach to a privileged process before the setuid permissions take effect.

MitigationUpgrade Linux kernel to version 2.6.30-rc4 or later, which contains the fix for the incorrect cred_exec_mutex locking in ptrace_attach. This is a kernel-level patch requiring system reboot.

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:<= 2.6.29= 2.6.30

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
Local
Complexity
M
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:L/AC:M/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. Identify installed kernel version
    Run `uname -r` or check `/proc/version` to obtain the running kernel version
    Affected if The kernel version is 2.6.29 or earlier, or exactly version 2.6.30
  2. Verify ptrace scope setting
    On some distributions, check the value of `/proc/sys/kernel/yama/ptrace_scope` (or older sysctl `kernel.ptrace_scope`). If using SELinux, also verify the ptrace policy with `getsebool allow_ptrace`
    Affected if ptrace is unrestricted (value 0 or 1) and the kernel version is affected, allowing any local user to invoke ptrace
  3. Confirm presence of setuid binaries
    List setuid programs with `find / -perm -4000 -type f 2>/dev/null`
    Affected if Any setuid binaries exist on the system and the kernel version is affected, creating potential targets for the race condition

A system is affected if it runs Linux kernel version 2.6.30 or any version 2.6.29 and earlier, and permits unprivileged ptrace operations against setuid processes.

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.

From vendor data
Upgrade available Upgrade to a release after 2.6.29
Interim mitigation

Upgrade Linux kernel to version 2.6.30-rc4 or later, which contains the fix for the incorrect cred_exec_mutex locking in ptrace_attach. This is a kernel-level patch requiring system reboot.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

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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-2009-1527 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