What is CVE-2009-1243?

CVE-2009-1243 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a Improper Locking flaw (CWE-667). CVE-2009-1243 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2009-1243?

CVE-2009-1243 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2009-1243?

No patch is currently available for CVE-2009-1243. Monitor the NIST NVD and your Linux distribution's security advisories for updates.

Is CVE-2009-1243 actively exploited?

CVE-2009-1243 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Improper Locking (CWE-667)?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/667.html

CVE-2009-1243

Medium

net/ipv4/udp.c in the Linux kernel before 2.6.29.1 performs an unlocking step in certain incorrect circumstances, which allows local users to cause a denial of service (panic) by reading zero bytes from the /proc/net/udp file and unspecified other files, related to the "udp seq_file infrastructure."

Package Linux Kernel

Published 2009-04-06

Last modified 2026-04-23

CVSS version 3.1

Patch available

Awaiting data

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-667

CVE-2009-1243 is a Improper Locking vulnerability

What is Improper Locking?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. Learn more on MITRE CWE

References

The following references provide additional information about CVE-2009-1243 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Secunia
http://secunia.com/advisories/34478

Broken Link Third Party Advisory
Kernel.org
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.29.1

Broken Link
Vupen
http://www.vupen.com/english/advisories/2009/0924

Broken Link Third Party Advisory
Exchange
https://exchange.xforce.ibmcloud.com/vulnerabilities/49595

Third Party Advisory VDB Entry
Kernel patch commit
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=30842f2989aacfaba3ccb39829b3417be9313dbe
Patch
Kernel patch commit
http://openwall.com/lists/oss-security/2009/04/01/4
Patch
Kernel patch commit
http://vigilance.fr/vulnerability/Linux-kernel-denial-of-service-via-proc-net-udp-8586
Patch

4 patch commits total View all on NVD

Details

CVE ID CVE-2009-1243

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2009-04-06

Modified 2026-04-23

KEV No

Patch Awaiting data

Package linux

Frequently asked questions

What is CVE-2009-1243?

CVE-2009-1243 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as an Improper Locking flaw (CWE-667) . CVE-2009-1243 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2009-1243?

CVE-2009-1243 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2009-1243?

No patch is currently available for CVE-2009-1243. Monitor the NIST NVD and your Linux distribution's security advisories for updates.
Is CVE-2009-1243 actively exploited?

No — CVE-2009-1243 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
What is Improper Locking (CWE-667)?

The product does not properly acquire or release a lock, which can lead to unexpected behaviour. View CWE-667 on MITRE CWE →