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Fencer Vulns
medium 5.5

CVE-2025-38588 json

ipv6: prevent infinite loop in rt6_nlmsg_size()

published 2025-08-19 14 mo ago modified 2026-11-05 3 d ago also EUVD-2025-27917

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 6%
public exploits
0
none known

Summary

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

ipv6: prevent infinite loop in rt6_nlmsg_size()

While testing prior patch, I was able to trigger an infinite loop in rt6_nlmsg_size() in the following place:

list_for_each_entry_rcu(sibling, &f6i->fib6_siblings, fib6_siblings) { rt6_nh_nlmsg_size(sibling->fib6_nh, &nexthop_len); }

This is because fib6_del_route() and fib6_add_rt2node() uses list_del_rcu(), which can confuse rcu readers, because they might no longer see the head of the list.

Restart the loop if f6i->fib6_nsiblings is zero.

Patch / fix

  • Linux Linux 6.1.148, 6.6.102, 6.12, 6.12.42, 6.15.10, 6.16.1, 6.17
  • linux Debian 12 6.1.148-1
  • linux Debian 13 6.12.43-1
  • linux Debian 14 6.16.3-1

debian advisories DEBIAN-CVE-2025-38588

  • linux Ubuntu 24.04 LTS 6.8.0-100.100
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1046.49
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1047.50
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1043.48
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1044.44
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1046.52
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1030.33
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1047.51

ubuntu advisories UBUNTU-CVE-2025-38588

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

  • kernel-livepatch-MICRO-6-0_Update_4 Linux Micro 6.1, Linux Micro 6.0 16-1.2
  • kernel-livepatch-MICRO-6-0_Update_5 Linux Micro 6.1, Linux Micro 6.0 14-1.2
  • kernel-livepatch-MICRO-6-0_Update_7 Linux Micro 6.1, Linux Micro 6.0 11-1.2
  • kernel-livepatch-MICRO-6-0_Update_8 Linux Micro 6.1, Linux Micro 6.0 11-1.2
  • kernel-livepatch-MICRO-6-0_Update_9 Linux Micro 6.1, Linux Micro 6.0 11-1.2
  • kernel-livepatch-MICRO-6-0_Update_6 Linux Micro 6.1, Linux Micro 6.0 12-3.1
  • kernel-livepatch-SLE16_Update_0 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 5-160000.4.3
  • kernel-livepatch-SLE16-RT_Update_0 Linux Micro 6.2 4-160000.3.4

suse advisories SUSE-SU-2026:20275-1SUSE-SU-2026:20276-1SUSE-SU-2026:20390-1SUSE-SU-2026:20391-1SUSE-SU-2026:20272-1SUSE-SU-2026:20273-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.6.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.6.1

opensuse advisories openSUSE-SU-2025:20081-1

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-2025-38588 updated cvss 5.5

kernel: ipv6: prevent infinite loop in rt6_nlmsg_size()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 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
3 d ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% 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

Weakness
  • CWE-835 Loop with Unreachable Exit Condition
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.