How severe is CVE-2013-4563?

CVE-2013-4563 has a CVSS 2.0 base score of 7.1, rated high severity.

Is CVE-2013-4563 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2013-4563?

CVE-2013-4563 primarily affects Linux Linux Kernel. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2013-4563?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2013-4563 published?

CVE-2013-4563 was published on 2013-11-20 and last updated on 2026-06-16.

CVE-2013-4563

CVE-2013-4563 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 2.0 base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-189.

Key facts

Severity: High (CVSS 2.0 base score 7.1)
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-189
Affected product: Linux Linux Kernel
Published: 2013-11-20
Last modified: 2026-06-16

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.

Frequently asked questions

What is CVE-2013-4563?: 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.
How severe is CVE-2013-4563?: CVE-2013-4563 has a CVSS 2.0 base score of 7.1, rated high severity.
Is CVE-2013-4563 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2013-4563?: CVE-2013-4563 primarily affects Linux Linux Kernel. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2013-4563?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2013-4563 published?: CVE-2013-4563 was published on 2013-11-20 and last updated on 2026-06-16.

References

Affected products (3)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:-:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:13.10:*:*:*:*:*:*:*

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