01 Record

CVE-2026-31478

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()

CriticalPUBLISHEDCNA: Linux

CNA base score9.8 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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02 Description

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()

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 ImpacttotalSuccessful exploitation gives total 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

0.50% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 42.6% of scored records. A rank, not a probability.

NVD base score

9.8 (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:H/I:H/A:H

NVD analysis status

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

Red Hat severity

Low. 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

2026-04-22 13:54Z6 MO AGO

Last updated

2026-10-19 18:45Z9 DAYS AGO

Reserved

2026-03-09

Assigning CNA

Linux

Record state

PUBLISHED

Severity

Critical (CVSS 9.8)

CNA CVSS vector

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

Weaknesses

CWE-131Incorrect Calculation of Buffer SizeBase

Data version

5.2

Document digest

4a36136f93ed539c6c1a7be81d85748a070edaab5e2336ed7a69519db4077800

05 Affected products

VendorProductVersionsPlatforms

LinuxLinuxf2283680a80571ca82d710bc6ecd8f8beac67d63 to < 70b4c414889492c522b6e4331562360f49be2361, 9f297df20d93411c0b4ddad7f88ba04a7cd36e77 to < 9a7166f0ef8cbb7bb48dd05e2471d995566003f5, e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to < c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683, e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to < 6aef1765d6807e0f027cd87f6ac973eb0879a46d, e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to < 80824c7e527b70cf9039534e60aff592e8f209d1, e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to < 4cb537ae4f37d7d0f617815ed4bed7173fb50861, e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to < 0e55f63dd08f09651d39e1b709a91705a8a0ddcb, 5.15.145 to < 5.15.203, 6.1.71 to < 6.1.168, 6.6—

06 References

git.kernel.orghttps://git.kernel.org/stable/c/70b4c414889492c522b6e4331562360f49be2361
git.kernel.orghttps://git.kernel.org/stable/c/9a7166f0ef8cbb7bb48dd05e2471d995566003f5
git.kernel.orghttps://git.kernel.org/stable/c/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683
git.kernel.orghttps://git.kernel.org/stable/c/6aef1765d6807e0f027cd87f6ac973eb0879a46d
git.kernel.orghttps://git.kernel.org/stable/c/80824c7e527b70cf9039534e60aff592e8f209d1
git.kernel.orghttps://git.kernel.org/stable/c/4cb537ae4f37d7d0f617815ed4bed7173fb50861
git.kernel.orghttps://git.kernel.org/stable/c/0e55f63dd08f09651d39e1b709a91705a8a0ddcb

07 Fixed in

Debian 12

linux
Fixed in 6.1.170-1

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

Debian 13

linux
Fixed in 6.12.85-1

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

Debian 14

linux
Fixed in 6.19.11-1

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