Client hang via overflowing SMB error length
Published Sep 11, 2026 · Updated Sep 11, 2026
Integer overflow in the Linux SMB client allows remote attackers controlling an SMB server to hang a client via a crafted error context. In symlink_data(), ALIGN() wraps a near-maximum 32-bit ErrorDataLength to zero before the bounds check, so the parser advances by zero bytes and repeatedly examines stale data. The client must process a malicious SMB 3.1.1 symlink error response; the established consequence is a client-side infinite loop rather than data modification or code execution.
Summary
What happened
Integer overflow in the Linux SMB client allows remote attackers controlling an SMB server to hang a client via a crafted error context. In symlink_data(), ALIGN() wraps a near-maximum 32-bit ErrorDataLength to zero before the bounds check, so the parser advances by zero bytes and repeatedly examines stale data. The client must process a malicious SMB 3.1.1 symlink error response; the established consequence is a client-side infinite loop rather than data modification or code execution.
The record
- CVE
- CVE-2026-89634
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=2d046892a493d9760c35fdaefc3017f27f91b621
- Affected versionversion=6.0.16 <6.1
- Affected versionversion=6.1
- Affected versionversion=76894f3e2f71177747b8b4763fb180e800279585 <1f824f61d1df52392eaf0b74dfa5659d724fde30
- Affected versionversion=76894f3e2f71177747b8b4763fb180e800279585 <62656b024efc21c3230eade1a847f25871c3d2bb
- Affected versionversion=76894f3e2f71177747b8b4763fb180e800279585 <62a3025983c8c735a3c6fc85a59316f31b59af07
- Affected versionversion=76894f3e2f71177747b8b4763fb180e800279585 <657372ba6ea50b4474d2a6a610097eae8cd1f3e9
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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