CVE-2009-4021: Medium severity linux kernel vulnerability

Q: What is the severity of CVE-2009-4021?

CVE-2009-4021 is classified as a denial of service vulnerability in the Linux kernel.

Q: How do I fix CVE-2009-4021?

To fix CVE-2009-4021, upgrade to a patched version of the Linux kernel as specified by your distribution maintainers.

Q: Which Linux kernel versions are affected by CVE-2009-4021?

CVE-2009-4021 affects Linux kernel versions before 2.6.32-rc7.

Q: What type of attack is associated with CVE-2009-4021?

CVE-2009-4021 may allow attackers to cause a denial of service through a memory-consumption attack.

Q: Is CVE-2009-4021 specific to any Linux distributions?

CVE-2009-4021 impacts multiple Linux distributions running affected versions of the kernel.

Published Oct 22, 2009

Updated

Description of problem: fusedirectio() has a loop where requests are allocated in each iteration. if allocation fails, the loop is broken out and follows into an unconditional fuseputrequest() on that invalid pointer."

Upstream commit: http://git.kernel.org/linus/f60311d5f7670d9539b424e4ed8b5c0872fc9e83

This can be triggered when the system is low on memory, and when the fuserequestalloc() function called from fusegetreq() fails. The fuseputrequest() function will then dereference the invalid pointer returned, resulting in a kernel oops.

This was introduced in 413ef8cb (v2.6.14-rc1) and fixed in v2.6.32-rc7.

Other sources

The fusedirectio function in fs/fuse/file.c in the fuse subsystem in the Linux kernel before 2.6.32-rc7 might allow attackers to cause a denial of service (invalid pointer dereference and OOPS) via vectors possibly related to a memory-consumption attack.

— Red Hat

Affected Software

337 affected componentsFixes available

redhat/kernel-rt<0:2.6.24.7-146.el5

0:2.6.24.7-146.el5

redhat/kernel<0:2.6.18-164.11.1.el5

0:2.6.18-164.11.1.el5

Linux Linux kernel=2.6.27.29

Linux Linux kernel=2.6.27.12

Linux Linux kernel=2.6.20.6

Linux Linux kernel=2.6.20.9

Linux Linux kernel=2.6.11

Linux Linux kernel=2.6.23.4

Linux Linux kernel=2.6.22.15

Linux Linux kernel=2.6.16.16

Linux Linux kernel=2.6.18.7

Linux Linux kernel=2.6.17.12

Linux Linux kernel=2.6.16.39

Linux Linux kernel=2.6.27.3

Linux Linux kernel=2.6.31

Linux Linux kernel=2.6.29.3

Linux Linux kernel=2.6.21

Linux Linux kernel=2.6.16.9

Linux Linux kernel=2.6.31-rc4

Linux Linux kernel=2.6.17.9

Linux Linux kernel=2.6.32-rc1

Linux Linux kernel=2.6.11.2

Linux Linux kernel=2.6.27.1

Linux Linux kernel=2.6.5

Linux Linux kernel=2.6.32-rc5

Linux Linux kernel=2.6.15.3

Linux Linux kernel=2.6.27.30

Linux Linux kernel=2.6.11.10

Linux Linux kernel=2.6.24.7

Linux Linux kernel=2.6.1

Linux Linux kernel=2.6.16.43

Linux Linux kernel=2.6.16.6

Linux Linux kernel=2.6.31.3

Linux Linux kernel=2.6.16.8

Linux Linux kernel=2.6.20.13

Linux Linux kernel=2.6.22.4

Linux Linux kernel=2.6.14.7

Linux Linux kernel=2.6.27.18

Linux Linux kernel=2.6.13

Linux Linux kernel=2.6.17.2

Linux Linux kernel=2.6.13.3

Linux Linux kernel=2.6.23.13

Linux Linux kernel=2.6.11.8

Linux Linux kernel=2.6.24.2

Linux Linux kernel=2.6.26.5

Linux Linux kernel=2.6.16.34

Linux Linux kernel=2.6.25.20

Linux Linux kernel=2.6.27.21

Linux Linux kernel=2.6.23.7

Linux Linux kernel=2.6.17.8

Linux Linux kernel=2.6.14.4

Linux Linux kernel=2.6.14

Linux Linux kernel=2.6.25.5

Linux Linux kernel=2.6.17.4

Linux Linux kernel=2.6.16.18

Linux Linux kernel=2.6.27.27

Linux Linux kernel=2.6.17.14

Linux Linux kernel=2.6.10

Linux Linux kernel=2.6.23.8

Linux Linux kernel=2.6.16.45

Linux Linux kernel=2.6.22.12

Linux Linux kernel=2.6.25.18

Linux Linux kernel=2.6.14.3

Linux Linux kernel=2.6.29

Linux Linux kernel=2.6.18.3

Linux Linux kernel=2.6.16.37

Linux Linux kernel=2.6.11.6

Linux Linux kernel=2.6.16.48

Linux Linux kernel=2.6.11.11

Linux Linux kernel=2.6.16.13

Linux Linux kernel=2.6.27.10

Linux Linux kernel=2.6.3

Linux Linux kernel=2.6.31.4

Linux Linux kernel=2.6.21.6

Linux Linux kernel=2.6.26.6

Linux Linux kernel=2.6.22.1

Linux Linux kernel=2.6.27.17

Linux Linux kernel=2.6.16.4

Linux Linux kernel=2.6.23.16

Linux Linux kernel=2.6.31.6

Linux Linux kernel=2.6.17.3

Linux Linux kernel=2.6.24.1

Linux Linux kernel=2.6.20.5

Linux Linux kernel=2.6.22

Linux Linux kernel=2.6.28.4

Linux Linux kernel=2.6.4

Linux Linux kernel=2.6.27.16

Linux Linux kernel=2.6.26

Linux Linux kernel=2.6.16.15

Linux Linux kernel=2.6.27.20

Linux Linux kernel=2.6.15.6

Linux Linux kernel=2.6.26.3

Linux Linux kernel=2.6.20.16

Linux Linux kernel=2.6.15.1

Linux Linux kernel=2.6.11.5

Linux Linux kernel=2.6.28.2

Linux Linux kernel=2.6.25.9

Linux Linux kernel=2.6.19.3

Linux Linux kernel=2.6.27.4

Linux Linux kernel=2.6.27

Linux Linux kernel=2.6.19.4

Linux Linux kernel=2.6.25.13

Linux Linux kernel=2.6.28.5

Linux Linux kernel=2.6.19.1

Linux Linux kernel=2.6.18.4

Linux Linux kernel=2.6.16.1

Linux Linux kernel=2.6.18.1

Linux Linux kernel=2.6.20.21

Linux Linux kernel=2.6.31-rc1

Linux Linux kernel=2.6.27.13

Linux Linux kernel=2.6.23.1

Linux Linux kernel=2.6.2

Linux Linux kernel=2.6.14.5

Linux Linux kernel=2.6.13.2

Linux Linux kernel=2.6.17.5

Linux Linux kernel=2.6.18.5

Linux Linux kernel=2.6.21.1

Linux Linux kernel=2.6.16.32

Linux Linux kernel=2.6.13.5

Linux Linux kernel=2.6.16.57

Linux Linux kernel=2.6.16.49

Linux Linux kernel=2.6.25.3

Linux Linux kernel=2.6.17

Linux Linux kernel=2.6.24

Linux Linux kernel=2.6.31-rc6

Linux Linux kernel=2.6.31.1

Linux Linux kernel=2.6.19.2

Linux Linux kernel=2.6.26.2

Linux Linux kernel=2.6.21.4

Linux Linux kernel=2.6.16.11

Linux Linux kernel=2.6.20.17

Linux Linux kernel=2.6.16.14

Linux Linux kernel=2.6.20.12

Linux Linux kernel=2.6.16.25

Linux Linux kernel=2.6.27.15

Linux Linux kernel=2.6.16.21

Linux Linux kernel=2.6.16.33

Linux Linux kernel=2.6.30.7

Linux Linux kernel=2.6.8

Linux Linux kernel=2.6.16.28

Linux Linux kernel=2.6.17.10

Linux Linux kernel=2.6.21.5

Linux Linux kernel=2.6.25.15

Linux Linux kernel=2.6.14.1

Linux Linux kernel=2.6.23.15

Linux Linux kernel=2.6.16.23

Linux Linux kernel<=2.6.32

Linux Linux kernel=2.6.29.4

Linux Linux kernel=2.6.12.5

Linux Linux kernel=2.6.15.7

Linux Linux kernel=2.6.20

Linux Linux kernel=2.6.23.10

Linux Linux kernel=2.6.22.7

Linux Linux kernel=2.6.27.26

Linux Linux kernel=2.6.16.3

Linux Linux kernel=2.6.27.8

Linux Linux kernel=2.6.26.1

Linux Linux kernel=2.6.25.19

Linux Linux kernel=2.6.20.20

Linux Linux kernel=2.6.16.36

Linux Linux kernel=2.6.30.8

Linux Linux kernel=2.6.14.6

Linux Linux kernel=2.6.12.1

Linux Linux kernel=2.6.27.9

Linux Linux kernel=2.6.11.9

Linux Linux kernel=2.6.16.46

Linux Linux kernel=2.6.17.1

Linux Linux kernel=2.6.20.8

Linux Linux kernel=2.6.27.25

Linux Linux kernel=2.6.30.9

Linux Linux kernel=2.6.20.15

Linux Linux kernel=2.6.22.18

Linux Linux kernel=2.6.0

Linux Linux kernel=2.6.25.8

Linux Linux kernel=2.6.16.54

Linux Linux kernel=2.6.32-rc4

Linux Linux kernel=2.6.13.4

Linux Linux kernel=2.6.20.18

Linux Linux kernel=2.6.23.9

Linux Linux kernel=2.6.22.6

Linux Linux kernel=2.6.23.3

Linux Linux kernel=2.6.18.8

Linux Linux kernel=2.6.22.3

Linux Linux kernel=2.6.12.2

Linux Linux kernel=2.6.16.31

Linux Linux kernel=2.6.16.26

Linux Linux kernel=2.6.16.62

Linux Linux kernel=2.6.18.2

Linux Linux kernel=2.6.28.8

Linux Linux kernel=2.6.31-rc5

Linux Linux kernel=2.6.16.29

Linux Linux kernel=2.6.29.1

Linux Linux kernel=2.6.24.4

Linux Linux kernel=2.6.27.19

Linux Linux kernel=2.6.25.16

Linux Linux kernel=2.6.22.9

Linux Linux kernel=2.6.25.17

Linux Linux kernel=2.6.20.11

Linux Linux kernel=2.6.19

Linux Linux kernel=2.6.20.3

Linux Linux kernel=2.6.16

Linux Linux kernel=2.6.30.4

Linux Linux kernel=2.6.28.3

Linux Linux kernel=2.6.22.13

Linux Linux kernel=2.6.19.7

Linux Linux kernel=2.6.21.3

Linux Linux kernel=2.6.27.28

Linux Linux kernel=2.6.24.5

Linux Linux kernel=2.6.16.51

Linux Linux kernel=2.6.15.2

Linux Linux kernel=2.6.20.19

Linux Linux kernel=2.6.16.22

Linux Linux kernel=2.6.22.17

Linux Linux kernel=2.6.16.58

Linux Linux kernel=2.6.16.40

Linux Linux kernel=2.6.16.47

Linux Linux kernel=2.6.16.42

Linux Linux kernel=2.6.27.22

Linux Linux kernel=2.6.23.14

Linux Linux kernel=2.6.17.11

Linux Linux kernel=2.6.16.10

Linux Linux kernel=2.6.12.4

Linux Linux kernel=2.6.16.41

Linux Linux kernel=2.6.16.52

Linux Linux kernel=2.6.11.3

Linux Linux kernel=2.6.20.10

Linux Linux kernel=2.6.16.24

Linux Linux kernel=2.6.31-rc7

Linux Linux kernel=2.6.25.10

Linux Linux kernel=2.6.22.11

Linux Linux kernel=2.6.16.55

Linux Linux kernel=2.6.23

Linux Linux kernel=2.6.12.3

Linux Linux kernel=2.6.22.10

Linux Linux kernel=2.6.29.6

Linux Linux kernel=2.6.23.17

Linux Linux kernel=2.6.27.5

Linux Linux kernel=2.6.23.2

Linux Linux kernel=2.6.25.1

Linux Linux kernel=2.6.25.4

Linux Linux kernel=2.6.28.9

Linux Linux kernel=2.6.30.2

Linux Linux kernel=2.6.7

Linux Linux kernel=2.6.21.7

Linux Linux kernel=2.6.30.6

Linux Linux kernel=2.6.16.30

Linux Linux kernel=2.6.21.2

Linux Linux kernel=2.6.15.4

Linux Linux kernel=2.6.27.7

Linux Linux kernel=2.6.16.59

Linux Linux kernel=2.6.30.1

Linux Linux kernel=2.6.16.38

Linux Linux kernel=2.6.16.17

Linux Linux kernel=2.6.26.8

Linux Linux kernel=2.6.20.2

Linux Linux kernel=2.6.28.6

Linux Linux kernel=2.6.16.12

Linux Linux kernel=2.6.31.5

Linux Linux kernel=2.6.16.27

Linux Linux kernel=2.6.16.53

Linux Linux kernel=2.6.28.7

Linux Linux kernel=2.6.12.6

Linux Linux kernel=2.6.31-rc8

Linux Linux kernel=2.6.17.7

Linux Linux kernel=2.6.20.1

Linux Linux kernel=2.6.11.7

Linux Linux kernel=2.6.16.2

Linux Linux kernel=2.6.24.6

Linux Linux kernel=2.6.31-rc3

Linux Linux kernel=2.6.18.6

Linux Linux kernel=2.6.15

Linux Linux kernel=2.6.16.44

Linux Linux kernel=2.6.23.12

Linux Linux kernel=2.6.16.35

Linux Linux kernel=2.6.19.6

Linux Linux kernel=2.6.16.50

Linux Linux kernel=2.6.25.11

Linux Linux kernel=2.6.27.31

Linux Linux kernel=2.6.29.2

Linux Linux kernel=2.6.23.5

Linux Linux kernel=2.6.22.8

Linux Linux kernel=2.6.14.2

Linux Linux kernel=2.6.16.61

Linux Linux kernel=2.6.31-rc2

Linux Linux kernel=2.6.19.5

Linux Linux kernel=2.6.18

Linux Linux kernel=2.6.27.24

Linux Linux kernel=2.6.20.4

Linux Linux kernel=2.6.17.6

Linux Linux kernel=2.6.23.6

Linux Linux kernel=2.6.27.2

Linux Linux kernel=2.6.16.7

Linux Linux kernel=2.6.17.13

Linux Linux kernel=2.6.16.60

Linux Linux kernel=2.6.22.2

Linux Linux kernel=2.6.8.1

Linux Linux kernel=2.6.27.11

Linux Linux kernel=2.6.16.56

Linux Linux kernel=2.6.22.19

Linux Linux kernel=2.6.24.3

Linux Linux kernel=2.6.31.2

Linux Linux kernel=2.6.25

Linux Linux kernel=2.6.20.14

Linux Linux kernel=2.6.25.2

Linux Linux kernel=2.6.22.5

Linux Linux kernel=2.6.32-rc3

Linux Linux kernel=2.6.25.7

Linux Linux kernel=2.6.30.5

Linux Linux kernel=2.6.25.14

Linux Linux kernel=2.6.20.7

Linux Linux kernel=2.6.28.1

Linux Linux kernel=2.6.16.5

Linux Linux kernel=2.6.30

Linux Linux kernel=2.6.11.4

Linux Linux kernel=2.6.26.4

Linux Linux kernel=2.6.25.12

Linux Linux kernel=2.6.16.19

Linux Linux kernel=2.6.27.6

Linux Linux kernel=2.6.26.7

Linux Linux kernel=2.6.25.6

Linux Linux kernel=2.6.11.12

Linux Linux kernel=2.6.16.20

Linux Linux kernel=2.6.15.5

Linux Linux kernel=2.6.28.10

Linux Linux kernel=2.6.22.16

Linux Linux kernel=2.6.11.1

Linux Linux kernel=2.6.30.3

Linux Linux kernel=2.6.9

Linux Linux kernel=2.6.27.23

Linux Linux kernel=2.6.13.1

Linux Linux kernel=2.6.23.11

Linux Linux kernel=2.6.27.14

Linux Linux kernel=2.6.28

Linux Linux kernel=2.6.29.5

Linux Linux kernel=2.6.22.14

Linux Linux kernel=2.6.6

Linux Linux kernel=2.6.12

Event History

Oct 22, 2009

CVE Published

via Red Hat·12:00 AM

Nov 19, 2009

Data Sourced

via Red Hat·09:02 AM

DescriptionSeverityAffected Software

Nov 25, 2009

CVE Published

via MITRE·04:00 PM

Data Sourced

via MITRE·04:00 PM

Description

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

What is the severity of CVE-2009-4021?

CVE-2009-4021 is classified as a denial of service vulnerability in the Linux kernel.

How do I fix CVE-2009-4021?