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Fencer Intel
high 7.1

CVE-2013-4563 json

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,…

published 2013-11-19 12 y ago modified 2026-06-16 4 mo ago also EUVD-2013-4421

cvss
7.1
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.9%
EPSS 3.9% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

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.

Patch / fix

  • linux linux_kernel 3.12.4
  • linux Debian 14, Debian 13, Debian 12 3.11.10-1

debian advisories DEBIAN-CVE-2013-4563

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2013-4563 updated cvss 7.1

kernel: net: large udp packet over IPv6 over UFO-enabled device with TBF qdisc panic

  • Red Hat Enterprise Linux 5 kernel Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, python-perf, kernel-kdump, kernel-tools, +3 more Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.90% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/torvalds/linux/commit/0e033e04c2678dbbe74a46b23fffb7bb918c288e referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 7.1 AV:N/AC:M/Au:N/C:N/I:N/A:C

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.