Heap disclosure via malformed SMB symlink response
Published Apr 24, 2026 · Updated Apr 24, 2026
Out-of-bounds reads in the Linux kernel SMB client allow remote attackers to disclose heap data through a malicious SMB symlink response. The symlink_data() walker accepts truncated SMB 3.1.1 error contexts, while smb2_parse_symlink_response() applies a fixed PathBuffer offset that becomes too short when contexts are present. A client must process an attacker-controlled STATUS_STOPPED_ON_SYMLINK response; the exposed bytes reach local userspace through readlink(2).
Summary
What happened
Out-of-bounds reads in the Linux kernel SMB client allow remote attackers to disclose heap data through a malicious SMB symlink response. The symlink_data() walker accepts truncated SMB 3.1.1 error contexts, while smb2_parse_symlink_response() applies a fixed PathBuffer offset that becomes too short when contexts are present. A client must process an attacker-controlled STATUS_STOPPED_ON_SYMLINK response; the exposed bytes reach local userspace through readlink(2).
The record
- CVE
- CVE-2026-31613
- Published
- Apr 24, 2026
- Updated
- Apr 24, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-125
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 24, 2026CVE publishedPublication date reported by the CVE source.
- Apr 24, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <781902e069f4ecb6c3b83502f181972c1446110a
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a66ef2e7ed837325c5600f8617d5ee0a0a149fdd
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e0dd90d14cbbf318157ea8e3fb62ee68a28655ed
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What is affected?
Published CVSS scores
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Attacks
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Technologies
Your stack
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Your stack
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