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Fencer Vulns
medium 5.5

CVE-2025-38032 json

mr: consolidate the ipmr_can_free_table() checks.

published 2025-06-18 16 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-18620

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 5%
public exploits
0
none known

Summary

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

mr: consolidate the ipmr_can_free_table() checks.

Guoyu Yin reported a splat in the ipmr netns cleanup path:

WARNING: CPU: 2 PID: 14564 at net/ipv4/ipmr.c:440 ipmr_free_table net/ipv4/ipmr.c:440 [inline] WARNING: CPU: 2 PID: 14564 at net/ipv4/ipmr.c:440 ipmr_rules_exit+0x135/0x1c0 net/ipv4/ipmr.c:361 Modules linked in: CPU: 2 UID: 0 PID: 14564 Comm: syz.4.838 Not tainted 6.14.0 #1 Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:ipmr_free_table net/ipv4/ipmr.c:440 [inline] RIP: 0010:ipmr_rules_exit+0x135/0x1c0 net/ipv4/ipmr.c:361 Code: ff df 48 c1 ea 03 80 3c 02 00 75 7d 48 c7 83 60 05 00 00 00 00 00 00 5b 5d 41 5c 41 5d 41 5e e9 71 67 7f 00 e8 4c 2d 8a fd 90 <0f> 0b 90 eb 93 e8 41 2d 8a fd 0f b6 2d 80 54 ea 01 31 ff 89 ee e8 RSP: 0018:ffff888109547c58 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888108c12dc0 RCX: ffffffff83e09868 RDX: ffff8881022b3300 RSI: ffffffff83e098d4 RDI: 0000000000000005 RBP: ffff888104288000 R08: 0000000000000000 R09: ffffed10211825c9 R10: 0000000000000001 R11: ffff88801816c4a0 R12: 0000000000000001 R13: ffff888108c13320 R14: ffff888108c12dc0 R15: fffffbfff0b74058 FS: 00007f84f39316c0(0000) GS:ffff88811b100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f84f3930f98 CR3: 0000000113b56000 CR4: 0000000000350ef0 Call Trace: <TASK> ipmr_net_exit_batch+0x50/0x90 net/ipv4/ipmr.c:3160 ops_exit_list+0x10c/0x160 net/core/net_namespace.c:177 setup_net+0x47d/0x8e0 net/core/net_namespace.c:394 copy_net_ns+0x25d/0x410 net/core/net_namespace.c:516 create_new_namespaces+0x3f6/0xaf0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc3/0x180 kernel/nsproxy.c:228 ksys_unshare+0x78d/0x9a0 kernel/fork.c:3342 __do_sys_unshare kernel/fork.c:3413 [inline] __se_sys_unshare kernel/fork.c:3411 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3411 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xa6/0x1a0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f84f532cc29 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f84f3931038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f84f5615fa0 RCX: 00007f84f532cc29 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000400 RBP: 00007f84f53fba18 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f84f5615fa0 R15: 00007fff51c5f328 </TASK>

The running kernel has CONFIG_IP_MROUTE_MULTIPLE_TABLES disabled, and the sanity check for such build is still too loose.

Address the issue consolidating the relevant sanity check in a single helper regardless of the kernel configuration. Also share it between the ipv4 and ipv6 code.

Patch / fix

  • Linux Linux 6.14.9, 6.15
  • linux-aws-6.14 Ubuntu 24.04 LTS 6.14.0-1013.13~24.04.1
  • linux-gcp-6.14 Ubuntu 24.04 LTS 6.14.0-1016.17~24.04.1
  • linux-oem-6.14 Ubuntu 24.04 LTS 6.14.0-1012.12
  • linux-riscv-6.14 Ubuntu 24.04 LTS 6.14.0-32.32.1~24.04.1
  • linux-oracle-6.14 Ubuntu 24.04 LTS 6.14.0-1013.13~24.04.1
  • linux-azure-nvidia-6.14 Ubuntu 24.04 LTS 6.14.0-1007.7
  • linux-realtime-6.14 Ubuntu Pro Realtime 24.04 LTS 6.14.0-1012.12~24.04.1

ubuntu advisories UBUNTU-CVE-2025-38032

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

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-2025-38032 updated cvss 3.3

kernel: mr: consolidate the ipmr_can_free_table() checks.

  • 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 Red Hat Enterprise Linux 10 kernel
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more 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

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% 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.