What’s Vulnerable › Vulnerabilities

CVE-2013-4563

• Severity: high (CVSS 7.1 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2013-11-20 · updated 2026-06-16
• Weakness: CWE-189

Description

The udp6_ufo_fragment function in net/ipv6/udp_offload.c in the Linux kernel through 3.12, when UDP Fragmentation Offload (UFO) is enabled, does not properly perform a certain size comparison before inserting a fragment header, which allows remote attackers to cause a denial of service (panic) via a large IPv6 UDP packet, as demonstrated by use of the Token Bucket Filter (TBF) queueing discipline.

Affected products

• Canonical Ubuntu Linux: 12.04, 13.10
• Linux kernel: from 3.9.8 through 3.10.23; from 3.11 before 3.12.4 — fixed in 3.12.4

How to fix

Upgrade to a fixed version: Linux kernel 3.12.4. Check the vendor advisory for mitigations.

References

• http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=0e033e04c2678dbbe74a46b23fffb7bb918c288e
• http://lists.opensuse.org/opensuse-security-announce/2014-02/msg00003.html
• http://www.openwall.com/lists/oss-security/2013/11/13/9
• http://www.ubuntu.com/usn/USN-2113-1
• http://www.ubuntu.com/usn/USN-2117-1
• https://bugzilla.redhat.com/show_bug.cgi?id=1030015
• https://github.com/torvalds/linux/commit/0e033e04c2678dbbe74a46b23fffb7bb918c288e
• http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=0e033e04c2678dbbe74a46b23fffb7bb918c288e
• http://lists.opensuse.org/opensuse-security-announce/2014-02/msg00003.html
• http://www.openwall.com/lists/oss-security/2013/11/13/9
• http://www.ubuntu.com/usn/USN-2113-1
• http://www.ubuntu.com/usn/USN-2117-1

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