Privilege escalation via procfs execve race
Published Aug 19, 2026 · Updated Aug 20, 2026
Race condition in execve(2) in FreeBSD allows local users to gain root privileges by altering a SUID process during execution. The kernel installs the new SUID binary vmspace before updating credentials, so procfs or linprocfs debug-path checks still trust the caller's original UID and permit memory reads or writes against the target image in that window. Exploitation requires local code execution and a same-UID process that can reach procfs or linprocfs before the credential switch completes; successful writes can hand full system control to the attacker.
Summary
What happened
Race condition in execve(2) in FreeBSD allows local users to gain root privileges by altering a SUID process during execution. The kernel installs the new SUID binary vmspace before updating credentials, so procfs or linprocfs debug-path checks still trust the caller's original UID and permit memory reads or writes against the target image in that window. Exploitation requires local code execution and a same-UID process that can reach procfs or linprocfs before the credential switch completes; successful writes can hand full system control to the attacker.
The record
- CVE
- CVE-2026-49415
- Published
- Aug 19, 2026
- Updated
- Aug 20, 2026
- Vendor
- The FreeBSD Project
- Product
- FreeBSD
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 19, 2026CVE publishedPublication date reported by the CVE source.
- Aug 20, 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=14.3-RELEASE <p16
- Affected versionversion=14.4-RELEASE <p7
- Affected versionversion=15.0-RELEASE <p11
- Affected versionversion=15.1-RELEASE <p1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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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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