Linux kernel SMB client: out-of-bounds reads in move_smb2_ea_to_cifs()
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
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The SMB client in the Linux kernel reads ea_name_length and ea_value_length out of bounds in move_smb2_ea_to_cifs(). The while (src_size > 0) loop keeps iterating when the remaining src_size is too small for a complete smb2_ea_info structure. Red Hat rates the issue Moderate, and CISA has not added it to KEV.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix OOB struct field reads in move_smb2_ea_to_cifs() In move_smb2_ea_to_cifs(), the while (src_size > 0) loop condition is insufficient. It allows iteration to continue even if the remaining src_size is too small to contain a complete smb2_ea_info structure. Consequently, reads of ea_name_length and ea_value_length can occur out-of-bounds. Fix this by ensuring src_size >= sizeof(*src) before attempting to read any structure fields. Additionally, reject any next_entry_offset that is smaller than sizeof(*src) or that would advance the pointer beyond the available buffer. Note that for calls where the server returns a malformed EA list, the error returned to userspace changes from -ENODATA (getxattr) or -ERANGE (listxattr) to -EIO. This correctly signals a server protocol error rather than misleadingly indicating "attribute not present" or "output buffer too small".
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Install a kernel with the fix: 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.54, 7.2.8 or 7.3. The fix checks src_size against sizeof(*src) before reading fields and rejects any next_entry_offset smaller than that size or pointing past the buffer. Red Hat Enterprise Linux 8, 9 and 10 and OpenShift Container Platform 4 and 5 have no fix available yet.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.54, 7.2.8, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-06 Threatist record created from CVE-2026-98170
- 2026-10-06 Alias added: GHSA-qx7m-524h-7684
- 2026-10-07 Affected versions changed · Red Hat
- 2026-10-07 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@61812323c037a94e2e7f0db7ee740c34b126bffe · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Fix available: Linux/Linux@22886b1b7464613373c9a7d0af2ace029c50cd97, Linux/[email protected], Linux/[email protected] +3 · CNA
- 2026-10-30 3 new references · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/22886b1b7464613373c9a7d0af2ace029c50cd97
- https://git.kernel.org/stable/c/9d707a278c100c26d10fbbbd03988778ffc992ce
- https://git.kernel.org/stable/c/90a13af4c9b1369327395bababfe87c75599cc19
- https://git.kernel.org/stable/c/61812323c037a94e2e7f0db7ee740c34b126bffe
- https://git.kernel.org/stable/c/d3546cecbf81d98bf3b472d341f981eb48c04f47
- https://git.kernel.org/stable/c/34a3942e787b9c59758115bd65fe1ec89d68c7a4
- https://git.kernel.org/stable/c/13efcd37a9b3d6ffa1579c3dda3e29c893ed9bca
- https://git.kernel.org/stable/c/eeb5ef6083e1cefa2ef75041b5597ff228b8d7bb
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- 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
Sources
- CVE-2026-98170 · CVE Program
- CVE-2026-98170 · NVD
- FIRST EPSS
- GHSA-qx7m-524h-7684 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98170 · Red Hat security data · CC BY 4.0
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