# CVE-2026-99273: ksmbd: reserve space for the UTF-16 terminator in stream info

Status: published. Published: 2026-11-07. Updated: 2026-11-07.

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: reserve space for the UTF-16 terminator in stream info

smb_strtoUTF16() always writes a terminating zero UTF-16 unit after the
converted characters, but get_file_stream_info() budgets only
sizeof(struct smb2_file_stream_info) + streamlen * 2 for a stream entry
and sizeof(struct smb2_file_stream_info) + 7 * 2 for the trailing
"::$DATA" entry. When an entry exactly fills the 448-byte small response
buffer, the terminator is written two bytes past the allocation.

Reserve one extra UTF-16 unit in both budget checks. The terminator is
not part of the wire format, so the reported lengths are unchanged.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 06a751809ebd33e95b05bf733697318a17a4872b (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 0e64f89563164719ceb1aa33f2a8bfd6391fa340 (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < a025c4991a7d83edc4dd339e3ea86d8ff6226eca (affected, git); ≥ 0; < 6.18.61 (affected, semver); ≥ 0; < 7.3.2 (affected, semver). Source: CNA: Linux
- Linux / Linux: ≥ 6.18.61; ≤ 6.18.* (unaffected, semver); ≥ 7.3.2; ≤ 7.3.* (unaffected, semver); ≥ 7.4-rc1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/06a751809ebd33e95b05bf733697318a17a4872b (CNA: Linux)

- https://git.kernel.org/stable/c/0e64f89563164719ceb1aa33f2a8bfd6391fa340 (CNA: Linux)

- https://git.kernel.org/stable/c/a025c4991a7d83edc4dd339e3ea86d8ff6226eca (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-99273; retrieved 2026-11-07; source updated 2026-11-07

Revision: 4be78aeedc2ffa5a25913dec45a15b241feca5eb042d679ca67d733718bc9fed

Canonical: https://y2.dev/cve/CVE-2026-99273

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