Kernel code execution via unrefcounted DFS child sessions
Published May 19, 2024 · Updated Aug 5, 2026
Use-after-free in the Linux kernel SMB client allows remote attackers to crash the kernel or execute code through crafted DFS referrals. The DFS mount and failover paths retain child sessions from tcon->ses without incrementing every child's reference count, allowing a cifs_ses object to be freed while later code still dereferences it. Reachability requires an existing CIFS DFS mount that processes attacker-controlled referrals; successful exploitation can expose session material, corrupt kernel control flow, or panic the host.
Summary
What happened
Use-after-free in the Linux kernel SMB client allows remote attackers to crash the kernel or execute code through crafted DFS referrals. The DFS mount and failover paths retain child sessions from tcon->ses without incrementing every child's reference count, allowing a cifs_ses object to be freed while later code still dereferences it. Reachability requires an existing CIFS DFS mount that processes attacker-controlled referrals; successful exploitation can expose session material, corrupt kernel control flow, or panic the host.
The record
- CVE
- CVE-2024-35869
- Published
- May 19, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 19, 2024CVE publishedPublication date reported by the CVE source.
- Aug 5, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.2.15 <6.3
- Affected versionversion=6.3.2 <6.4
- Affected versionversion=6.4
- Affected versionversion=8e3554150d6c80a84b3cb046615d1a0e943811dc <062a7f0ff46eb57aff526897bd2bebfdb1d3046a
- Affected versionversion=8e3554150d6c80a84b3cb046615d1a0e943811dc <645f332c6b63499cc76197f9b6bffcc659ba64cc
- Affected versionversion=8e3554150d6c80a84b3cb046615d1a0e943811dc <e1db9ae87b7148c021daee1fcc4bc71b2ac58a79
- Affected versionversion=c082c3be0f96e759ff2e361d929832fda0b93851
- Affected versionversion=f30d226bcc9f0e2d97b4a6e94c43a28148fbeab6
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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