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Fencer Vulns
medium 5.5

CVE-2022-48910 json

net: ipv6: ensure we call ipv6_mc_down() at most once

published 2024-08-22 2 y ago modified 2026-06-17 4 mo ago also EUVD-2022-53789

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

net: ipv6: ensure we call ipv6_mc_down() at most once

There are two reasons for addrconf_notify() to be called with NETDEV_DOWN: either the network device is actually going down, or IPv6 was disabled on the interface.

If either of them stays down while the other is toggled, we repeatedly call the code for NETDEV_DOWN, including ipv6_mc_down(), while never calling the corresponding ipv6_mc_up() in between. This will cause a new entry in idev->mc_tomb to be allocated for each multicast group the interface is subscribed to, which in turn leaks one struct ifmcaddr6 per nontrivial multicast group the interface is subscribed to.

The following reproducer will leak at least $n objects:

ip addr add ff2e::4242/32 dev eth0 autojoin sysctl -w net.ipv6.conf.eth0.disable_ipv6=1 for i in $(seq 1 $n); do ip link set up eth0; ip link set down eth0 done

Joining groups with IPV6_ADD_MEMBERSHIP (unprivileged) or setting the sysctl net.ipv6.conf.eth0.forwarding to 1 (=> subscribing to ff02::2) can also be used to create a nontrivial idev->mc_list, which will the leak objects with the right up-down-sequence.

Based on both sources for NETDEV_DOWN events the interface IPv6 state should be considered:

- not ready if the network interface is not ready OR IPv6 is disabled for it - ready if the network interface is ready AND IPv6 is enabled for it

The functions ipv6_mc_up() and ipv6_down() should only be run when this state changes.

Implement this by remembering when the IPv6 state is ready, and only run ipv6_mc_down() if it actually changed from ready to not ready.

The other direction (not ready -> ready) already works correctly, as:

- the interface notification triggered codepath for NETDEV_UP / NETDEV_CHANGE returns early if ipv6 is disabled, and - the disable_ipv6=0 triggered codepath skips fully initializing the interface as long as addrconf_link_ready(dev) returns false - calling ipv6_mc_up() repeatedly does not leak anything

Patch / fix

  • Linux Linux 4.9.313, 4.14.278, 4.19.323, 5.4.193, 5.10.104, 5.15.27, 5.16.13, 5.17
  • linux Debian 14, Debian 13, Debian 12 5.16.14-1

debian advisories DEBIAN-CVE-2022-48910

  • linux Ubuntu 18.04 LTS 4.15.0-191.202
  • linux Ubuntu 20.04 LTS 5.4.0-124.140
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1139.150
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1083.90
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1086.94
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1031.35
  • linux-iot Ubuntu 20.04 LTS 5.4.0-1004.6
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1125.130

ubuntu advisories UBUNTU-CVE-2022-48910

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dtb-aarch64 openSUSE Leap 15.5 5.14.21-150500.55.80.1
  • kernel-64kb SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.2
  • kernel-syms SLE Module for Development Tools 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.1
  • kernel-obs-qa openSUSE Leap 15.5 5.14.21-150500.55.80.1
  • kernel-source SLE Module for Development Tools 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.2
  • kernel-default SLE Workstation Extension 15 SP5, SLE Module for Legacy 15 SP5, SLE Module for Basesystem 15 SP5 +5 more 5.14.21-150500.55.80.2
  • kernel-kvmsmall openSUSE Leap 15.5 5.14.21-150500.55.80.2
  • kernel-zfcpdump SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.80.2

suse advisories SUSE-SU-2024:3483-1SUSE-SU-2024:3252-1SUSE-SU-2024:3251-1SUSE-SU-2024:3209-1SUSE-SU-2024:3190-1SUSE-SU-2024:3189-1

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-2022-48910 updated cvss 5.5

kernel: net: ipv6: ensure we call ipv6_mc_down() at most once

  • 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, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns 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.