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Fencer Vulns
high 7.2

CVE-2009-4141 json

Use-after-free vulnerability in the fasync_helper function in fs/fcntl.c in the Linux kernel before 2.6.33-rc4-git1 allows local users to g…

published 2010-01-19 16 y ago modified 2026-06-16 4 mo ago also EUVD-2009-4111

cvss
7.2
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
1
Exploit-DB

Summary

Use-after-free vulnerability in the fasync_helper function in fs/fcntl.c in the Linux kernel before 2.6.33-rc4-git1 allows local users to gain privileges via vectors that include enabling O_ASYNC (aka FASYNC or FIOASYNC) on a locked file, and then closing this file.

Patch / fix

  • kernel RHEL 5 2.6.18-164.11.1.el5
  • kernel-PAE RHEL 5 2.6.18-164.11.1.el5
  • kernel-xen RHEL 5 2.6.18-164.11.1.el5
  • kernel-kdump RHEL 5 2.6.18-164.11.1.el5
  • kernel-debuginfo-common RHEL 5 2.6.18-164.11.1.el5
  • kernel-rt enterprise mrg 1 2.6.24.7-149.el5rt
  • kernel-rt-trace enterprise mrg 1 2.6.24.7-149.el5rt
  • kernel-rt-vanilla enterprise mrg 1 2.6.24.7-149.el5rt

red hat advisories RHSA-2010:0046RHSA-2010:0161RHSA-2010:0149

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-4141 updated cvss 7.2

kernel: create_elf_tables can leave urandom in a bad state

  • Red Hat MRG Realtime for RHEL 5 Server kernel-rt 2.6.24.7-149.el5rt, kernel-rt-trace 2.6.24.7-149.el5rt, kernel-rt-vanilla 2.6.24.7-149.el5rt, kernel-rt-debuginfo-common 2.6.24.7-149.el5rt
    fixed: vendor fix RHSA-2010:0161
  • Red Hat Enterprise Linux (v. 5 server) kernel 2.6.18-164.11.1.el5, kernel-PAE 2.6.18-164.11.1.el5, kernel-xen 2.6.18-164.11.1.el5, kernel-kdump 2.6.18-164.11.1.el5, kernel-debuginfo-common 2.6.18-164.11.1.el5 Red Hat Enterprise Linux Desktop (v. 5 client) kernel 2.6.18-164.11.1.el5, kernel-PAE 2.6.18-164.11.1.el5, kernel-xen 2.6.18-164.11.1.el5, kernel-debuginfo-common 2.6.18-164.11.1.el5
    fixed: vendor fix RHSA-2010:0046
  • Red Hat Enterprise Linux EUS (v. 5.3 server) kernel 2.6.18-128.14.1.el5, kernel-PAE 2.6.18-128.14.1.el5, kernel-xen 2.6.18-128.14.1.el5, kernel-kdump 2.6.18-128.14.1.el5, kernel-debuginfo-common 2.6.18-128.14.1.el5
    fixed: vendor fix RHSA-2010:0149
  • Red Hat Enterprise Linux (v. 5 server) kernel-headers 2.6.18-164.11.1.el5 Red Hat Enterprise Linux Desktop (v. 5 client) kernel-headers 2.6.18-164.11.1.el5 Red Hat Enterprise Linux EUS (v. 5.3 server) kernel-headers 2.6.18-128.14.1.el5
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. First public exploit (EDB-33523)
  2. Published

Exploit prediction

0.97% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-33523 Linux Kernel < 2.6.28 - 'fasync_helper()' Local Privilege Escalation local, 2009-12-16
  • archives.neohapsis.com http://archives.neohapsis.com/archives/fulldisclosure/2010-01/0252.html referenced PoC, tagged "exploit" by a source, unverified
  • lock.cmpxchg8b.com http://lock.cmpxchg8b.com/5ebe2294ecd0e0f08eab7690d2a6ee69/create_elf_tables.c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-399 Resource Management Errors
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.