5.5

CVE-2024-36889: mptcp: ensure snd_nxt is properly initialized on connect

Analyzed
AliasesUBUNTU-CVE-2024-36889DEBIAN-CVE-2024-36889
Published 30-05-2024Last modified 11-05-2026

Vulnerability summary

CVE-2024-36889 is a medium (CVSS 5.5) vulnerability in debian debian_linux. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.27%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 31 · Related 20
DLA-3843-1DSA-5703-1MGASA-2024-0263MGASA-2024-0266RHSA-2024:10262RHSA-2024:5101

Timeline

  1. 30-05-2024
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.27%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.27% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu116 products
  • linux< 5.15.0-118.128 | < 6.8.0-40.40
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 5.15.0-1067.73 | < 6.8.0-1013.14
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
Linux2 products
  • linux≥ 8fd738049ac3d67a937d36577763b47180aae1ad, < 99951b62bf20cec9247f633a3bea898338b9e5b4 | ≥ 8fd738049ac3d67a937d36577763b47180aae1ad, < dc941fec0719d0471a5902424d6b2a17df233193 | ≥ 8fd738049ac3d67a937d36577763b47180aae1ad, < 39ca83ed73db9edcc6d70c0dc7a73085a4725012 | ≥ 8fd738049ac3d67a937d36577763b47180aae1ad, < aa0c07c1f20e05b30019bff083ec43665536f06f | ≥ 8fd738049ac3d67a937d36577763b47180aae1ad, < 592f69b41766d366dbb8ff4ef5a67c4396527bbe | ≥ 8fd738049ac3d67a937d36577763b47180aae1ad, < fb7a0d334894206ae35f023a82cad5a290fd7386 | 5.9
  • linux_kernel≥ 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:rc1 | 6.9:rc2 | 6.9:rc3 | 6.9:rc4 | 6.9:rc5 | 6.9:rc6

3 vendors · 120 products

References

23 links
Show all 23 references