01 Record

CVE-2026-89554

mptcp: fix uninitialized local_id in syncookie MP_JOIN reconstruction

HighPUBLISHEDCNA: Linux

CNA base score8.2 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

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02 Description

mptcp: fix uninitialized local_id in syncookie MP_JOIN reconstruction

03 Exploitation and scoring

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.59% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 48.4% of scored records. A rank, not a probability.

NVD base score

8.2 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

NVD analysis status

Received. NVD last modified this record on 2026-10-19.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2026-09-11 19:44Z1 MO AGO

Last updated

2026-10-19 08:48Z10 DAYS AGO

Reserved

2026-09-11

Assigning CNA

Linux

Record state

PUBLISHED

Severity

High (CVSS 8.2)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Weaknesses

CWE-824Access of Uninitialized PointerBase

Data version

5.2

Document digest

840b5ab6466562e2b493eeb3c19f9a04d5d68b664280c4f73c40cdedb523b45b

05 Affected products

VendorProductVersionsPlatforms

LinuxLinux9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < 4534e0eead692bb069ad1e6a5a245fc2e2078300, 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < 63cacb05e51a1c6e1349d2e593d00fd6ef43def4, 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < 954b5ea836eb118d188975ced803448537ab8479, 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < 9df36a4846375a9b75bf42d77bfed216b0f366f9, 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < 64f2c5dd49b956a542c8c02b8dad5d262a462bba, 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < 51887ccd88791ddaa8755a7c614fda031ecf7982, 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < bf19d166337c6488b39cb03eeeffb30a941d6326, 9466a1ccebbe54ac57fb8a89c2b4b854826546a8 to < b878dfdd12d7a5b8722a78d35e313506140ca3d9, 5.9—

06 References

git.kernel.orghttps://git.kernel.org/stable/c/4534e0eead692bb069ad1e6a5a245fc2e2078300
git.kernel.orghttps://git.kernel.org/stable/c/63cacb05e51a1c6e1349d2e593d00fd6ef43def4
git.kernel.orghttps://git.kernel.org/stable/c/954b5ea836eb118d188975ced803448537ab8479
git.kernel.orghttps://git.kernel.org/stable/c/9df36a4846375a9b75bf42d77bfed216b0f366f9
git.kernel.orghttps://git.kernel.org/stable/c/64f2c5dd49b956a542c8c02b8dad5d262a462bba
git.kernel.orghttps://git.kernel.org/stable/c/51887ccd88791ddaa8755a7c614fda031ecf7982
git.kernel.orghttps://git.kernel.org/stable/c/bf19d166337c6488b39cb03eeeffb30a941d6326
git.kernel.orghttps://git.kernel.org/stable/c/b878dfdd12d7a5b8722a78d35e313506140ca3d9

07 Fixed in

Debian 12

linux
Fixed in 6.1.190-1
linux-6.12
Fixed in 6.12.111-1~deb12u1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

linux
Fixed in 6.12.111-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

linux
Fixed in 7.2.6-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.