Kernel disclosure and crash via bypassed length validation
Published Aug 22, 2026 · Updated Aug 25, 2026
Out-of-bounds read in the Linux ATM subsystem allows local users to disclose kernel memory or crash the host through setsockopt. An ineffective optlen check in vcc_setsockopt() can be bypassed by a mismatched level or a cgroup BPF filter, causing copy_from_sockptr() to read past a short kernel buffer. Any unprivileged local user in the initial network namespace can reach the syscall without user interaction; the bounded effects are disclosure and a kernel oops or panic.
Summary
What happened
Out-of-bounds read in the Linux ATM subsystem allows local users to disclose kernel memory or crash the host through setsockopt. An ineffective optlen check in vcc_setsockopt() can be bypassed by a mismatched level or a cgroup BPF filter, causing copy_from_sockptr() to read past a short kernel buffer. Any unprivileged local user in the initial network namespace can reach the syscall without user interaction; the bounded effects are disclosure and a kernel oops or panic.
The record
- CVE
- CVE-2026-74689
- Published
- Aug 22, 2026
- Updated
- Aug 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-805, T1005
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Aug 22, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2c5988c7349c0b64a7e0441bfc6e1dca54f7116a
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <35f258fee9ed358c6d0f57f91c30bf029c3724af
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6eb6af88710977eb529b558a07294874d8c40c4d
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9f77c1ab382188f5b51982fab6d913443b6dc59f
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b3bcd5d65ac03c15787b2a5b36c718e26a689336
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3
- Affected versionversion=2.6.12
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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