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Fencer Vulns
medium 5.5

CVE-2024-36889 json

mptcp: ensure snd_nxt is properly initialized on connect

published 2024-05-30 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-36241

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

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

mptcp: ensure snd_nxt is properly initialized on connect

Christoph reported a splat hinting at a corrupted snd_una:

WARNING: CPU: 1 PID: 38 at net/mptcp/protocol.c:1005 __mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005 Modules linked in: CPU: 1 PID: 38 Comm: kworker/1:1 Not tainted 6.9.0-rc1-gbbeac67456c9 #59 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 Workqueue: events mptcp_worker RIP: 0010:__mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005 Code: be 06 01 00 00 bf 06 01 00 00 e8 a8 12 e7 fe e9 00 fe ff ff e8 8e 1a e7 fe 0f b7 ab 3e 02 00 00 e9 d3 fd ff ff e8 7d 1a e7 fe <0f> 0b 4c 8b bb e0 05 00 00 e9 74 fc ff ff e8 6a 1a e7 fe 0f 0b e9 RSP: 0018:ffffc9000013fd48 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff8881029bd280 RCX: ffffffff82382fe4 RDX: ffff8881003cbd00 RSI: ffffffff823833c3 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: fefefefefefefeff R12: ffff888138ba8000 R13: 0000000000000106 R14: ffff8881029bd908 R15: ffff888126560000 FS: 0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f604a5dae38 CR3: 0000000101dac002 CR4: 0000000000170ef0 Call Trace: <TASK> __mptcp_clean_una_wakeup net/mptcp/protocol.c:1055 [inline] mptcp_clean_una_wakeup net/mptcp/protocol.c:1062 [inline] __mptcp_retrans+0x7f/0x7e0 net/mptcp/protocol.c:2615 mptcp_worker+0x434/0x740 net/mptcp/protocol.c:2767 process_one_work+0x1e0/0x560 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x3c7/0x640 kernel/workqueue.c:3416 kthread+0x121/0x170 kernel/kthread.c:388 ret_from_fork+0x44/0x50 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 </TASK>

When fallback to TCP happens early on a client socket, snd_nxt is not yet initialized and any incoming ack will copy such value into snd_una. If the mptcp worker (dumbly) tries mptcp-level re-injection after such ack, that would unconditionally trigger a send buffer cleanup using 'bad' snd_una values.

We could easily disable re-injection for fallback sockets, but such dumb behavior already helped catching a few subtle issues and a very low to zero impact in practice.

Instead address the issue always initializing snd_nxt (and write_seq, for consistency) at connect time.

Patch / fix

  • Linux Linux 5.10.218, 5.15.159, 6.1.91, 6.6.31, 6.8.10, 6.9
  • linux Debian 12 6.1.94-1
  • linux Debian 14, Debian 13 6.8.11-1

debian advisories DEBIAN-CVE-2024-36889

  • linux Ubuntu 22.04 LTS 5.15.0-118.128
  • linux Ubuntu 24.04 LTS 6.8.0-40.40
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1067.73
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1013.14
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1066.74
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1012.13
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1064.70
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1008.11

ubuntu advisories UBUNTU-CVE-2024-36889

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 5.14.0-427.40.1.el9_4
  • rv RHEL 9 5.14.0-427.40.1.el9_4
  • perf RHEL 9 5.14.0-427.40.1.el9_4
  • rtla RHEL 9 5.14.0-427.40.1.el9_4
  • bpftool RHEL 9 7.3.0-427.40.1.el9_4
  • libperf RHEL 9 5.14.0-427.40.1.el9_4
  • kernel-rt RHEL 9 5.14.0-427.40.1.el9_4
  • kernel-64k RHEL 9 5.14.0-427.40.1.el9_4

red hat advisories RHSA-2024:10262RHSA-2024:8614RHSA-2024:8613RHSA-2024:8162RHSA-2024:5102RHSA-2024:5101

  • 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-2024:2947-1SUSE-SU-2024:2939-1SUSE-SU-2024:2896-1

  • kernel AlmaLinux 9 5.14.0-427.40.1.el9_4
  • rv AlmaLinux 9 5.14.0-427.40.1.el9_4
  • perf AlmaLinux 9 5.14.0-427.40.1.el9_4
  • rtla AlmaLinux 9 5.14.0-427.40.1.el9_4
  • bpftool AlmaLinux 9 7.3.0-427.40.1.el9_4
  • libperf AlmaLinux 9 5.14.0-427.40.1.el9_4
  • kernel-rt AlmaLinux 9 5.14.0-427.40.1.el9_4
  • kernel-64k AlmaLinux 9 5.14.0-427.40.1.el9_4

almalinux advisories ALSA-2024:8162ALSA-2024:5101ALSA-2024:5102

  • kernel Rocky Linux 9 5.14.0-427.40.1.el9_4
  • kernel Rocky Linux 8 4.18.0-553.16.1.el8_10.cloud.0.1
  • kernel-rt Rocky Linux 8 4.18.0-553.16.1.rt7.357.el8_10
  • kernel Rocky Linux 8 4.18.0-553.16.1.el8_10

rocky linux advisories RLSA-2024:8162RXSA-2024:5101RLSA-2024:5102RLSA-2024:5101

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-2024-36889 updated cvss 5.5

kernel: mptcp: ensure snd_nxt is properly initialized on connect

  • 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 4.18.0-477.81.1.el8_8, kernel-debuginfo-common-aarch64 4.18.0-477.81.1.el8_8, kernel-debuginfo-common-ppc64le 4.18.0-477.81.1.el8_8
    fixed: vendor fix RHSA-2024:10262
  • Red Hat CodeReady Linux Builder EUS (v.9.2) kernel-debuginfo-common-s390x 5.14.0-284.90.1.el9_2, kernel-debuginfo-common-x86_64 5.14.0-284.90.1.el9_2, kernel-debuginfo-common-aarch64 5.14.0-284.90.1.el9_2, kernel-debuginfo-common-ppc64le 5.14.0-284.90.1.el9_2
    fixed: vendor fix RHSA-2024:8613
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-427.40.1.el9_4, perf 5.14.0-427.40.1.el9_4, rtla 5.14.0-427.40.1.el9_4, kernel-devel-matched 5.14.0-427.40.1.el9_4, kernel-64k-devel-matched 5.14.0-427.40.1.el9_4, kernel-debug-devel-matched 5.14.0-427.40.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:8162
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) perf 5.14.0-284.90.1.el9_2, rtla 5.14.0-284.90.1.el9_2, kernel-devel-matched 5.14.0-284.90.1.el9_2, kernel-64k-devel-matched 5.14.0-284.90.1.el9_2, kernel-debug-devel-matched 5.14.0-284.90.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.90.1.el9_2, +5 more
    fixed: vendor fix RHSA-2024:8613
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.16.1.el8_10, kernel 4.18.0-553.16.1.el8_10, bpftool 4.18.0-553.16.1.el8_10, kernel-core 4.18.0-553.16.1.el8_10, kernel-tools 4.18.0-553.16.1.el8_10, python3-perf 4.18.0-553.16.1.el8_10, +15 more
    fixed: vendor fix RHSA-2024:5101
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.40.1.el9_4, kernel 5.14.0-427.40.1.el9_4, kernel-64k 5.14.0-427.40.1.el9_4, kernel-core 5.14.0-427.40.1.el9_4, kernel-tools 5.14.0-427.40.1.el9_4, python3-perf 5.14.0-427.40.1.el9_4, +28 more
    fixed: vendor fix RHSA-2024:8162
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) perf 4.18.0-372.124.1.el8_6, kernel 4.18.0-372.124.1.el8_6, bpftool 4.18.0-372.124.1.el8_6, kernel-core 4.18.0-372.124.1.el8_6, kernel-tools 4.18.0-372.124.1.el8_6, python3-perf 4.18.0-372.124.1.el8_6, +8 more Red Hat Enterprise Linux BaseOS E4S (v.8.6) perf 4.18.0-372.124.1.el8_6, kernel 4.18.0-372.124.1.el8_6, bpftool 4.18.0-372.124.1.el8_6, kernel-core 4.18.0-372.124.1.el8_6, kernel-tools 4.18.0-372.124.1.el8_6, python3-perf 4.18.0-372.124.1.el8_6, +15 more
    fixed: vendor fix RHSA-2024:6998
show 11 more
  • Red Hat Enterprise Linux BaseOS EUS (v.8.8) perf 4.18.0-477.81.1.el8_8, kernel 4.18.0-477.81.1.el8_8, bpftool 4.18.0-477.81.1.el8_8, kernel-core 4.18.0-477.81.1.el8_8, kernel-tools 4.18.0-477.81.1.el8_8, python3-perf 4.18.0-477.81.1.el8_8, +15 more
    fixed: vendor fix RHSA-2024:10262
  • Red Hat Enterprise Linux BaseOS EUS (v.9.2) bpftool 7.0.0-284.90.1.el9_2, kernel 5.14.0-284.90.1.el9_2, kernel-64k 5.14.0-284.90.1.el9_2, kernel-core 5.14.0-284.90.1.el9_2, kernel-tools 5.14.0-284.90.1.el9_2, python3-perf 5.14.0-284.90.1.el9_2, +28 more
    fixed: vendor fix RHSA-2024:8613
  • Red Hat Enterprise Linux BaseOS TUS (v.8.6) perf 4.18.0-372.124.1.el8_6, kernel 4.18.0-372.124.1.el8_6, bpftool 4.18.0-372.124.1.el8_6, kernel-core 4.18.0-372.124.1.el8_6, kernel-tools 4.18.0-372.124.1.el8_6, python3-perf 4.18.0-372.124.1.el8_6, +8 more
    fixed: vendor fix RHSA-2024:6998
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.16.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.16.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.16.1.el8_10
    fixed: vendor fix RHSA-2024:5101
  • Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.40.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.40.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.40.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.40.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.40.1.el9_4
    fixed: vendor fix RHSA-2024:8162
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-kvm 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-core 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-modules 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-kvm 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-core 4.18.0-553.16.1.rt7.357.el8_10, +4 more
    fixed: vendor fix RHSA-2024:5102
  • Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.40.1.el9_4, kernel-rt-kvm 5.14.0-427.40.1.el9_4, kernel-rt-core 5.14.0-427.40.1.el9_4, kernel-rt-modules 5.14.0-427.40.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.40.1.el9_4, kernel-rt-debug-core 5.14.0-427.40.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:8162
  • Red Hat Enterprise Linux Real Time EUS (v.9.2) kernel-rt 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-core 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-modules 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-debug-core 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-modules-core 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-debug-modules 5.14.0-284.90.1.rt14.375.el9_2, +4 more Red Hat Enterprise Linux Real Time for NFV EUS (v.9.2) kernel-rt 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-kvm 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-core 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-modules 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-debug-kvm 5.14.0-284.90.1.rt14.375.el9_2, kernel-rt-debug-core 5.14.0-284.90.1.rt14.375.el9_2, +6 more
    fixed: vendor fix RHSA-2024:8614
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-core 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-modules 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-core 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-debug-modules 4.18.0-553.16.1.rt7.357.el8_10, kernel-rt-modules-extra 4.18.0-553.16.1.rt7.357.el8_10, +2 more
    fixed: vendor fix RHSA-2024:5102
  • Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.40.1.el9_4, kernel-rt-core 5.14.0-427.40.1.el9_4, kernel-rt-modules 5.14.0-427.40.1.el9_4, kernel-rt-debug-core 5.14.0-427.40.1.el9_4, kernel-rt-modules-core 5.14.0-427.40.1.el9_4, kernel-rt-debug-modules 5.14.0-427.40.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:8162
  • 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 AppStream EUS (v.9.2) kernel-doc 5.14.0-284.90.1.el9_2
    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-25-226-15 updated cvss 0.0

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

0.27% chance of exploitation in the next 30 days, higher than 18% 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.