CVE-2013-4563

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

3.9% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2013-11-20 13:19 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:57 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.9% in the next 30 days (EPSS).
• Severity: 7.1 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2013-11-20 13:19 UTC

Last modified

2026-06-16 23:57 UTC

Exploit probability

3.9% · EPSS, next 30 days

Weakness

CWE-189

Record status

Modified

Affected

• Linux Kernel ≤ 3.10.23
• Linux Kernel < 3.12.4
• Canonical Ubuntu Linux 12.04
• Canonical Ubuntu Linux 13.10

Attack profile CVSS 2.0 · 7.1

Attack vector

Network

Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

Is it in your code?

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