CVE-2026-58098 is a vulnerability in FreeBSD
Published on October 15, 2026
Heap out-of-bounds access in semop(2)
When semop(2) blocks waiting for a semaphore condition, it releases the per-set lock and sleeps. Upon waking, it checks the sequence number embedded in the semaphore set's IPC identifier to detect whether the set was removed while the caller was asleep. This sequence number is only 15 bits wide. If enough semaphore sets are created and destroyed in the same table slot while a caller is blocked, the counter wraps around, and semop(2) may falsely conclude that the original set still exists. The subsequent access to a semaphore within the set may then be out of bounds.
An unprivileged local user can trigger an out-of-bounds access on kernel heap memory, potentially leading to privilege escalation.
Weakness Type
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-58098 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2026-58098
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Affected Versions
FreeBSD:- Version 15.1-RELEASE and below p4 is affected.
- Version 15.0-RELEASE and below p14 is affected.
- Version 14.5-RELEASE and below p1 is affected.
- Version 14.4-RELEASE and below p10 is affected.