CVE-2026-98281: futex: Also allocate private hash on vfork()
In the Linux kernel, the following vulnerability has been resolved:
futex: Also allocate private hash on vfork()
As Jann demonstrated, it is entirely feasible to access the mm through vfork(). Therefore we need to allocate a private hash on vfork() as well as any other CLONEVM user.
Specifically, it must be avoided to have (private) futex waiters before allocating the private hash.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
What runtime conditions are relevant to this issue?
The issue concerns Linux kernel paths using vfork() or other CLONE_VM users where private futex waiters can exist before a private futex hash has been allocated. Access to the memory descriptor through vfork() is specifically identified as feasible.
What is the available remediation information?
The vulnerability is described as resolved by allocating a private futex hash on vfork(), as is done for other CLONE_VM users. Three stable kernel commit references are provided for the fix, but no affected or fixed kernel version ranges are included.