CVE-2026-52973: Linux kernel · futex: Drop CLONE_THREAD requirement for private default hash alloc
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in ee9dce44362b2d8132c32964656ab6dff7dfbc6a : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in ee9dce44362b2d8132c32964656ab6dff7dfbc6a, 974ac49a9a068b0591a59f65c63eb06579a13091, 1dcd36420af2da5bd59306dba9caf78e3d248b1d
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Linux kernel to ee9dce44362b2d8132c32964656ab6dff7dfbc6a, 974ac49a9a068b0591a59f65c63eb06579a13091 or 1dcd36420af2da5bd59306dba9caf78e3d248b1d.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: futex: Drop CLONE_THREAD requirement for private default hash alloc Currently need_futex_hash_allocate_default() depends on strict pthread semantics, abusing CLONE_THREAD. This breaks the non-concurrency assumptions when doing the mm->futex_ref pcpu allocations, leading to bugs[0] when sharing the mm in other ways; ie: BUG: KASAN: slab-use-after-free in futex_hash_put ... where the +1 bias can end up on a percpu counter that mm->futex_ref no longer points at. Loosen the check to cover any CLONE_VM clone, except vfork(). Excluding vfork keeps the existing paths untouched (no overhead), and we can't race in the first place: either the parent is suspended and the child runs alone, or mm->futex_ref is already allocated from an earlier CLONE_VM.
References
- git.kernel.org/stable/c/1dcd36420af2da5bd59306dba9caf78e3d248b1d (opens in a new tab)
- git.kernel.org/stable/c/974ac49a9a068b0591a59f65c63eb06579a13091 (opens in a new tab)
- git.kernel.org/stable/c/ee9dce44362b2d8132c32964656ab6dff7dfbc6a (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-52973 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2492413 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52973.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:45114 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:47040 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62642 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62640 (opens in a new tab)