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Fencer Vulns
high 8.8

CVE-2024-35969 json

ipv6: fix race condition between ipv6_get_ifaddr and ipv6_del_addr

published 2024-05-20 2 y ago modified 2026-10-15 25 d ago also EUVD-2024-35687

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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

ipv6: fix race condition between ipv6_get_ifaddr and ipv6_del_addr

Although ipv6_get_ifaddr walks inet6_addr_lst under the RCU lock, it still means hlist_for_each_entry_rcu can return an item that got removed from the list. The memory itself of such item is not freed thanks to RCU but nothing guarantees the actual content of the memory is sane.

In particular, the reference count can be zero. This can happen if ipv6_del_addr is called in parallel. ipv6_del_addr removes the entry from inet6_addr_lst (hlist_del_init_rcu(&ifp->addr_lst)) and drops all references (__in6_ifa_put(ifp) + in6_ifa_put(ifp)). With bad enough timing, this can happen:

1. In ipv6_get_ifaddr, hlist_for_each_entry_rcu returns an entry.

2. Then, the whole ipv6_del_addr is executed for the given entry. The reference count drops to zero and kfree_rcu is scheduled.

3. ipv6_get_ifaddr continues and tries to increments the reference count (in6_ifa_hold).

4. The rcu is unlocked and the entry is freed.

5. The freed entry is returned.

Prevent increasing of the reference count in such case. The name in6_ifa_hold_safe is chosen to mimic the existing fib6_info_hold_safe.

[ 41.506330] refcount_t: addition on 0; use-after-free. [ 41.506760] WARNING: CPU: 0 PID: 595 at lib/refcount.c:25 refcount_warn_saturate+0xa5/0x130 [ 41.507413] Modules linked in: veth bridge stp llc [ 41.507821] CPU: 0 PID: 595 Comm: python3 Not tainted 6.9.0-rc2.main-00208-g49563be82afa #14 [ 41.508479] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) [ 41.509163] RIP: 0010:refcount_warn_saturate+0xa5/0x130 [ 41.509586] Code: ad ff 90 0f 0b 90 90 c3 cc cc cc cc 80 3d c0 30 ad 01 00 75 a0 c6 05 b7 30 ad 01 01 90 48 c7 c7 38 cc 7a 8c e8 cc 18 ad ff 90 <0f> 0b 90 90 c3 cc cc cc cc 80 3d 98 30 ad 01 00 0f 85 75 ff ff ff [ 41.510956] RSP: 0018:ffffbda3c026baf0 EFLAGS: 00010282 [ 41.511368] RAX: 0000000000000000 RBX: ffff9e9c46914800 RCX: 0000000000000000 [ 41.511910] RDX: ffff9e9c7ec29c00 RSI: ffff9e9c7ec1c900 RDI: ffff9e9c7ec1c900 [ 41.512445] RBP: ffff9e9c43660c9c R08: 0000000000009ffb R09: 00000000ffffdfff [ 41.512998] R10: 00000000ffffdfff R11: ffffffff8ca58a40 R12: ffff9e9c4339a000 [ 41.513534] R13: 0000000000000001 R14: ffff9e9c438a0000 R15: ffffbda3c026bb48 [ 41.514086] FS: 00007fbc4cda1740(0000) GS:ffff9e9c7ec00000(0000) knlGS:0000000000000000 [ 41.514726] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 41.515176] CR2: 000056233b337d88 CR3: 000000000376e006 CR4: 0000000000370ef0 [ 41.515713] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 41.516252] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 41.516799] Call Trace: [ 41.517037] <TASK> [ 41.517249] ? __warn+0x7b/0x120 [ 41.517535] ? refcount_warn_saturate+0xa5/0x130 [ 41.517923] ? report_bug+0x164/0x190 [ 41.518240] ? handle_bug+0x3d/0x70 [ 41.518541] ? exc_invalid_op+0x17/0x70 [ 41.520972] ? asm_exc_invalid_op+0x1a/0x20 [ 41.521325] ? refcount_warn_saturate+0xa5/0x130 [ 41.521708] ipv6_get_ifaddr+0xda/0xe0 [ 41.522035] inet6_rtm_getaddr+0x342/0x3f0 [ 41.522376] ? __pfx_inet6_rtm_getaddr+0x10/0x10 [ 41.522758] rtnetlink_rcv_msg+0x334/0x3d0 [ 41.523102] ? netlink_unicast+0x30f/0x390 [ 41.523445] ? __pfx_rtnetlink_rcv_msg+0x10/0x10 [ 41.523832] netlink_rcv_skb+0x53/0x100 [ 41.524157] netlink_unicast+0x23b/0x390 [ 41.524484] netlink_sendmsg+0x1f2/0x440 [ 41.524826] __sys_sendto+0x1d8/0x1f0 [ 41.525145] __x64_sys_sendto+0x1f/0x30 [ 41.525467] do_syscall_64+0xa5/0x1b0 [ 41.525794] entry_SYSCALL_64_after_hwframe+0x72/0x7a [ 41.526213] RIP: 0033:0x7fbc4cfcea9a [ 41.526528] Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89 [ 41.527942] RSP: 002b:00007f ---truncated---

Patch / fix

  • Linux Linux 4.19.313, 5.4.275, 5.10.216, 5.15.156, 6.1.87, 6.6.28, 6.8.7, 6.9
  • Siemens RUGGEDCOM RST2428P V3.1
  • Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family V3.1
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem V1.1.1
  • linux Debian 12 6.1.90-1
  • linux Debian 14, Debian 13 6.8.9-1

debian advisories DEBIAN-CVE-2024-35969

  • linux Ubuntu 20.04 LTS 5.4.0-189.209
  • linux Ubuntu 22.04 LTS 5.15.0-116.126
  • linux Ubuntu 24.04 LTS 6.8.0-38.38
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1128.138
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1065.71
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1011.12
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1132.141
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1064.72

ubuntu advisories UBUNTU-CVE-2024-35969

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 RHEL 9 5.14.0-427.31.1.el9_4
  • rv RHEL 9 5.14.0-427.31.1.el9_4
  • perf RHEL 9 5.14.0-427.31.1.el9_4
  • rtla RHEL 9 5.14.0-427.31.1.el9_4
  • bpftool RHEL 9 7.3.0-427.31.1.el9_4
  • libperf RHEL 9 5.14.0-427.31.1.el9_4
  • kernel-rt RHEL 9 5.14.0-427.31.1.el9_4
  • kernel-64k RHEL 9 5.14.0-427.31.1.el9_4

red hat advisories RHSA-2024:6993RHSA-2024:5363RHSA-2024:4554RHSA-2024:4533RHSA-2024:4447

  • kernel-rt Linux Micro 6.0 6.4.0-9.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-9.1
  • kernel-source Linux Micro 6.0 6.4.0-18.1
  • kernel-default Linux Micro 6.0 6.4.0-18.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-18.1
  • kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
  • kernel-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.5.1
  • kernel-syms-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.5.1

suse advisories SUSE-SU-2025:20028-1SUSE-SU-2025:20008-1SUSE-SU-2024:2973-1SUSE-SU-2024:2203-1SUSE-SU-2024:2190-1SUSE-SU-2024:2184-1

  • kernel AlmaLinux 9 5.14.0-427.31.1.el9_4
  • rv AlmaLinux 9 5.14.0-427.31.1.el9_4
  • perf AlmaLinux 9 5.14.0-427.31.1.el9_4
  • rtla AlmaLinux 9 5.14.0-427.31.1.el9_4
  • bpftool AlmaLinux 9 7.3.0-427.31.1.el9_4
  • libperf AlmaLinux 9 5.14.0-427.31.1.el9_4
  • kernel-rt AlmaLinux 9 5.14.0-427.31.1.el9_4
  • kernel-64k AlmaLinux 9 5.14.0-427.31.1.el9_4

almalinux advisories ALSA-2024:5363

  • kernel Rocky Linux 9 5.14.0-427.31.1.el9_4

rocky linux advisories RLSA-2024:5363

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-2024-35969 updated cvss 5.5

kernel: ipv6: fix race condition between ipv6_get_ifaddr and ipv6_del_addr

  • 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: 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 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available
  • Red Hat CodeReady Linux Builder EUS (v.8.8) kernel-debuginfo-common-x86_64 4.18.0-477.74.1.el8_8, kernel-debuginfo-common-aarch64 4.18.0-477.74.1.el8_8, kernel-debuginfo-common-ppc64le 4.18.0-477.74.1.el8_8
    fixed: vendor fix RHSA-2024:6993
  • Red Hat CodeReady Linux Builder EUS (v.9.2) kernel-debuginfo-common-s390x 5.14.0-284.73.1.el9_2, kernel-debuginfo-common-x86_64 5.14.0-284.73.1.el9_2, kernel-debuginfo-common-aarch64 5.14.0-284.73.1.el9_2, kernel-debuginfo-common-ppc64le 5.14.0-284.73.1.el9_2
    fixed: vendor fix RHSA-2024:4533
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-427.31.1.el9_4, perf 5.14.0-427.31.1.el9_4, rtla 5.14.0-427.31.1.el9_4, kernel-devel-matched 5.14.0-427.31.1.el9_4, kernel-64k-devel-matched 5.14.0-427.31.1.el9_4, kernel-debug-devel-matched 5.14.0-427.31.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:5363
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) perf 5.14.0-284.73.1.el9_2, rtla 5.14.0-284.73.1.el9_2, kernel-devel-matched 5.14.0-284.73.1.el9_2, kernel-64k-devel-matched 5.14.0-284.73.1.el9_2, kernel-debug-devel-matched 5.14.0-284.73.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.73.1.el9_2, +5 more
    fixed: vendor fix RHSA-2024:4533
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.31.1.el9_4, kernel 5.14.0-427.31.1.el9_4, kernel-64k 5.14.0-427.31.1.el9_4, kernel-core 5.14.0-427.31.1.el9_4, kernel-tools 5.14.0-427.31.1.el9_4, python3-perf 5.14.0-427.31.1.el9_4, +28 more
    fixed: vendor fix RHSA-2024:5363
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) perf 4.18.0-372.111.1.el8_6, kernel 4.18.0-372.111.1.el8_6, bpftool 4.18.0-372.111.1.el8_6, kernel-core 4.18.0-372.111.1.el8_6, kernel-tools 4.18.0-372.111.1.el8_6, python3-perf 4.18.0-372.111.1.el8_6, +8 more Red Hat Enterprise Linux BaseOS E4S (v.8.6) perf 4.18.0-372.111.1.el8_6, kernel 4.18.0-372.111.1.el8_6, bpftool 4.18.0-372.111.1.el8_6, kernel-core 4.18.0-372.111.1.el8_6, kernel-tools 4.18.0-372.111.1.el8_6, python3-perf 4.18.0-372.111.1.el8_6, +15 more
    fixed: vendor fix RHSA-2024:4447
show 7 more
  • Red Hat Enterprise Linux BaseOS EUS (v.8.8) perf 4.18.0-477.74.1.el8_8, kernel 4.18.0-477.74.1.el8_8, bpftool 4.18.0-477.74.1.el8_8, kernel-core 4.18.0-477.74.1.el8_8, kernel-tools 4.18.0-477.74.1.el8_8, python3-perf 4.18.0-477.74.1.el8_8, +15 more
    fixed: vendor fix RHSA-2024:6993
  • Red Hat Enterprise Linux BaseOS EUS (v.9.2) bpftool 7.0.0-284.73.1.el9_2, kernel 5.14.0-284.73.1.el9_2, kernel-64k 5.14.0-284.73.1.el9_2, kernel-core 5.14.0-284.73.1.el9_2, kernel-tools 5.14.0-284.73.1.el9_2, python3-perf 5.14.0-284.73.1.el9_2, +28 more
    fixed: vendor fix RHSA-2024:4533
  • Red Hat Enterprise Linux BaseOS TUS (v.8.6) perf 4.18.0-372.111.1.el8_6, kernel 4.18.0-372.111.1.el8_6, bpftool 4.18.0-372.111.1.el8_6, kernel-core 4.18.0-372.111.1.el8_6, kernel-tools 4.18.0-372.111.1.el8_6, python3-perf 4.18.0-372.111.1.el8_6, +8 more
    fixed: vendor fix RHSA-2024:4447
  • Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.31.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.31.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.31.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.31.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.31.1.el9_4 Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.31.1.el9_4, kernel-rt-kvm 5.14.0-427.31.1.el9_4, kernel-rt-core 5.14.0-427.31.1.el9_4, kernel-rt-modules 5.14.0-427.31.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.31.1.el9_4, kernel-rt-debug-core 5.14.0-427.31.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:5363
  • Red Hat Enterprise Linux Real Time EUS (v.9.2) kernel-rt 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-core 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-modules 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-debug-core 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-modules-core 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-debug-modules 5.14.0-284.73.1.rt14.358.el9_2, +4 more Red Hat Enterprise Linux Real Time for NFV EUS (v.9.2) kernel-rt 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-kvm 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-core 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-modules 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-debug-kvm 5.14.0-284.73.1.rt14.358.el9_2, kernel-rt-debug-core 5.14.0-284.73.1.rt14.358.el9_2, +6 more
    fixed: vendor fix RHSA-2024:4554
  • Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.31.1.el9_4, kernel-rt-core 5.14.0-427.31.1.el9_4, kernel-rt-modules 5.14.0-427.31.1.el9_4, kernel-rt-debug-core 5.14.0-427.31.1.el9_4, kernel-rt-modules-core 5.14.0-427.31.1.el9_4, kernel-rt-debug-modules 5.14.0-427.31.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:5363
  • Red Hat Enterprise Linux AppStream (v. 9) kernel-headers 5.14.0-427.31.1.el9_4 Red Hat Enterprise Linux AppStream EUS (v.9.2) kernel-doc 5.14.0-284.73.1.el9_2 Red Hat Enterprise Linux CRB (v. 9) kernel-cross-headers 5.14.0-427.31.1.el9_4
    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 ICSA-24-102-01 updated cvss 5.5

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-25-226-15 updated cvss 5.5

Siemens SINEC OS

  • Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) < 3.1 Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family < 3.1
    affected: fixed in V3.1 support.industry.siemens.com
  • Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family
    not affected

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADP 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA 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
  • Siemens RUGGEDCOM RST2428P
  • Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family
  • Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling
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.