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TI-2026-86597 Aliases CVE-2026-99273GHSA-3jvj-587v-w544

Out-of-bounds write in Linux kernel ksmbd stream info

Priority LOW 38Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
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Impact type
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Confidentiality · integrity · availability
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Fix status
Fixed

No CVSS vector from any source. Fix status from CNA.

Summary

The ksmbd SMB server in the Linux kernel before 6.18.61 and before 7.3.2 can write a terminating UTF-16 zero two bytes past its response buffer. The stream info size checks in get_file_stream_info() do not reserve space for that terminator, so a stream entry that exactly fills the 448-byte small response buffer causes an out-of-bounds write.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

Description from the CNA

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.

Why it matters now

Fix Fixed Linux (Linux): 6.18.61, 7.3.2, 7.4-rc1

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinuxbefore 6.18.61; before 7.3.26.18.61, 7.3.2Patch availableCNA
LinuxLinux—6.18.61, 7.3.2, 7.4-rc1Patch availableCNA
  • Linux VendorLinux Affected before 6.18.61; before 7.3.2 Fixed in 6.18.61, 7.3.2 Patch available CNA
  • Linux VendorLinux Affected — Fixed in 6.18.61, 7.3.2, 7.4-rc1 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

The fixed versions are Linux kernel 6.18.61, 7.3.2 and 7.4-rc1.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

  • Fix · CNA Linux (Linux) Fixed in 6.18.61, 7.3.2
  • Fix · CNA Linux (Linux) Fixed in 6.18.61, 7.3.2, 7.4-rc1

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 7 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5

Timeline

  1. 2026-11-07 Threatist record created from CVE-2026-99273
  2. 2026-11-07 Alias added: GHSA-3jvj-587v-w544
  3. 2026-11-08 Affected versions changed · Red Hat
  4. 2026-11-08 CVSS score added · Red Hat

References

Other 3

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences