Linux KernelOperating system · Linux
CVE-2024-36889
A fix is available.
Upgrade to 5.10.218 / 5.15.159 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click
Patch available
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisA detailed technical summary for this CVE is being prepared.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
Affected:
>= 5.9, < 5.10.218>= 5.11, < 5.15.159>= 5.16, < 6.1.91>= 6.2, < 6.6.31>= 6.7, < 6.8.10= 6.9
Debian LinuxOperating system
Affected:
= 10.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped
Upgrade available
Upgrade to 5.10.218 / 5.15.159 / 6.1.91 or later
Fixed in
5.10.2185.15.1596.1.91
Vendor patch
git.kernel.org →
Recommended fix
High confidence
Upgrade to the next stable kernel release in your current major version branch that contains the fix (5.10.218+, 5.15.159+, 6.1.91+, or 6.6.31+)
- Identify the currently running kernel version using 'uname -r'
- For systems running kernel 5.9.x through 5.10.x: upgrade to kernel 5.10.218 or later but below 5.11
- For systems running kernel 5.11.x through 5.15.x: upgrade to kernel 5.15.159 or later but below 5.16
- For systems running kernel 5.16.x through 6.1.x: upgrade to kernel 6.1.91 or later but below 6.2
- For systems running kernel 6.2.x through 6.6.x: upgrade to kernel 6.6.31 or later but below 6.7
- For Debian 10 (Buster) systems: apply Debian kernel security updates that include this fix, or upgrade to Debian 11/12 which ship with fixed kernels
- Reboot the system after applying the kernel update
Caveat Kernel upgrades typically require system downtime for reboot; ensure compatibility of other software with the newer kernel before upgrading in production environments
Generated from the published advisory — verify against the referenced sources before acting.
We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600.
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Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-36889 in production — separate from our analysis above.
Know something about CVE-2024-36889?
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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