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CVE-2009-4895

Publication date 8 September 2010

Last updated 24 July 2024

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

4.7 · Medium

Score breakdown

Race condition in the tty_fasync function in drivers/char/tty_io.c in the Linux kernel before 2.6.32.6 allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact via unknown vectors, related to the put_tty_queue and __f_setown functions. NOTE: the vulnerability was addressed in a different way in 2.6.32.9.

From the Ubuntu Security Team

Al Viro discovered a race condition in the TTY driver. A local attacker could exploit this to crash the system, leading to a denial of service.

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 10.10 maverick
Not affected
10.04 LTS lucid
Not affected
9.10 karmic
Fixed 2.6.31-22.67
9.04 jaunty
Fixed 2.6.28-19.66
8.04 LTS hardy
Not affected
6.06 LTS dapper Not in release
linux-ec2 10.10 maverick Ignored end of life
10.04 LTS lucid
Fixed 2.6.32-309.18
9.10 karmic
Fixed 2.6.31-307.21
8.04 LTS hardy Not in release
6.06 LTS dapper Not in release
linux-fsl-imx51 10.10 maverick Not in release
10.04 LTS lucid
Fixed 2.6.31-608.22
9.10 karmic
Fixed 2.6.31-112.30
8.04 LTS hardy Not in release
6.06 LTS dapper Not in release
linux-lts-backport-maverick 10.10 maverick Not in release
10.04 LTS lucid
Fixed 2.6.35-25.44~lucid1
9.10 karmic Not in release
8.04 LTS hardy Not in release
6.06 LTS dapper Not in release
linux-source-2.6.15 10.10 maverick Not in release
10.04 LTS lucid Not in release
9.10 karmic Not in release
9.04 jaunty Not in release
8.04 LTS hardy Not in release
6.06 LTS dapper
Not affected

Notes

sbeattie

first patch (703625118069f9f8) was reverted and the second patch was used in 2.6.32.9, which fixes the issue "properly".

smb

IMO the races in tty became visible when the BLK was pushed down into the line disciplines and switch to unlocked ioctl in 2.6.26 (04f378b198da233ca0aca341b113dc6579d46123), so Hardy and Dapper are not affected.

Severity score breakdown

Parameter Value
Base score 4.7 · Medium
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-1074-1
    • Linux kernel vulnerabilities
    • 25 February 2011
    • USN-1083-1
    • Linux kernel vulnerabilities
    • 3 March 2011
    • USN-1000-1
    • Linux kernel vulnerabilities
    • 19 October 2010
    • USN-1074-2
    • Linux kernel vulnerabilities
    • 28 February 2011

Other references