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Fencer Intel
high 7.1

CVE-2011-4326 json

The udp6_ufo_fragment function in net/ipv6/udp.c in the Linux kernel before 2.6.39, when a certain UDP Fragmentation Offload (UFO) configur…

published 2012-05-17 14 y ago modified 2026-06-16 4 mo ago also EUVD-2011-4258

cvss
7.1
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

The udp6_ufo_fragment function in net/ipv6/udp.c in the Linux kernel before 2.6.39, when a certain UDP Fragmentation Offload (UFO) configuration is enabled, allows remote attackers to cause a denial of service (system crash) by sending fragmented IPv6 UDP packets to a bridge device.

Patch / fix

  • linux linux_kernel 2.6.39
  • kernel RHEL 6 2.6.32-131.21.1.el6
  • perf RHEL 6 2.6.32-131.21.1.el6
  • kernel-kdump RHEL 6 2.6.32-131.21.1.el6
  • kernel-firmware RHEL 6 2.6.32-131.21.1.el6
  • kernel-bootwrapper RHEL 6 2.6.32-131.21.1.el6
  • kernel-debuginfo-common-i686 RHEL 6 2.6.32-131.21.1.el6
  • kernel-debuginfo-common-ppc64 RHEL 6 2.6.32-131.21.1.el6
  • kernel-debuginfo-common-s390x RHEL 6 2.6.32-131.21.1.el6

red hat advisories RHSA-2011:1465RHSA-2012:0010

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-2011-4326 updated cvss 7.1

kernel: wrong headroom check in udp6_ufo_fragment()

  • Red Hat Enterprise Linux Server (v. 6) perf 2.6.32-131.21.1.el6, kernel 2.6.32-131.21.1.el6, kernel-kdump 2.6.32-131.21.1.el6, kernel-firmware 2.6.32-131.21.1.el6, kernel-bootwrapper 2.6.32-131.21.1.el6, kernel-debuginfo-common-i686 2.6.32-131.21.1.el6, +3 more
    fixed: vendor fix RHSA-2011:1465
  • Red Hat MRG Realtime for RHEL 6 Server v.2 kernel-rt 2.6.33.9-rt31.79.el6rt, kernel-rt-trace 2.6.33.9-rt31.79.el6rt, kernel-rt-vanilla 2.6.33.9-rt31.79.el6rt, kernel-rt-firmware 2.6.33.9-rt31.79.el6rt, kernel-rt-debuginfo-common-x86_64 2.6.33.9-rt31.79.el6rt
    fixed: vendor fix RHSA-2012:0010
  • Red Hat Enterprise Linux 4 kernel Red Hat Enterprise Linux 5 kernel
    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

3.18% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=682066 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
  • CWE-399 Resource Management Errors
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.