CVE-2026-98454: Linux Vulnerability (CVSS 8.1)

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix create context out-of-bounds reads smb2_parse_contexts() validates the complete create-context area but does not limit each record to its Next field before dispatching it. A malformed chain can therefore expose bytes beyond the current context to a handler. The QFid handler also used a full response-structure cast although it only reads DiskFileId. The SMB2/SMB3 lease parsers made the same layout assumption: they read LeaseState and LeaseFlags at canonical offsets rather than at DataOffset. A valid non-canonical DataOffset could therefore yield unrelated in-bounds data, while a short DataLength was still accepted. Limit each context to its Next value, reject offsets before the context header, and reject malformed chains. Bound the name range by the current context and do not dispatch a known handler when DataLength is zero. Read the QFid DiskFileId only when the context data covers that field. Parse the lease context from DataOffset and require DataLength to match the v1 or v2 lease_context size used by ksmbd. A size mismatch skips lease parsing without failing the open.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

0.34%

27.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < 34245048d6c1fa6d7be4f0dec1d14b5be02360e1; >= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < 0a8c2a6715c2a67b7abbbf874fccc9f5518146d9; >= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < 43d0ca48bb902d554b6531862248810d2ae3b8ef; >= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < e4c49012708c917eafd9c27054b02d0f8b30fe64; >= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < 28bc9a871799363afa3139e961a8e3684feb8704; >= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < 05a7fd80024ff32b9b40ab1478bb172eeab1c386; >= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < cecc5399987e73a528ce2b662eeb54af69163cbd; >= b8c32dbb0deb287a5fcb78251e4eae6c7275760d, < 67f4c1c6a1b51e203d986779299824d1c2c590a6
Linux	Linux	3.7

References

Timeline

Published: Oct 18, 2026
Last Modified: Oct 30, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-98454?

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix create context out-of-bounds reads smb2_parse_contexts() validates the complete create-context area but does not limit each record to its Next field before dispatching it. A malformed chain can therefore expose bytes beyond the current context to a handler. The QFid handler also used a full response-structure cast although it only reads DiskFileId. The SMB2/SMB3 lease parsers made the same layout assumption: they read LeaseState and LeaseFlags at canonical offsets rather than at DataOffset. A valid non-canonical DataOffset could therefore yield unrelated in-bounds data, while a short DataLength was still accepted. Limit each context to its Next value, reject offsets before the context header, and reject malformed chains. Bound the name range by the current context and do not dispatch a known handler when DataLength is zero. Read the QFid DiskFileId only when the context data covers that field. Parse the lease context from DataOffset and require DataLength to match the v1 or v2 lease_context size used by ksmbd. A size mismatch skips lease parsing without failing the open.

How severe is CVE-2026-98454?

CVE-2026-98454 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.

How do I fix CVE-2026-98454?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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