TI-2026-55788 Aliases CVE-2026-80775 GHSA-f29q-mg8h-pcrg

futex: Fix race on the initial mm->futex.phash.ref allocation

LOW 22Published 2026-09-04 · Updated 2026-10-19

Key facts

Attack vector: —
Privileges required: —
User interaction: —
Attack complexity: —
Impact type: —
Confidentiality · integrity · availability: —
Fix status: Partial Red Hat: 13 fixed, 1 without a fix

No CVSS vector from any source. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: futex: Fix race on the initial mm->futex.phash.ref allocation futex_hash_allocate() allocates mm->futex.phash.ref without any locking. Commit d9b05321e21e ("futex: Move futex_hash_free() back to __mmput()") moved the allocation here and assumed that the process has just a single thread at this point. Commit ee9dce44362b ("futex: Drop CLONE_THREAD requirement for private default hash alloc") widened need_futex_hash_allocate_default() to cover any CLONE_VM clone, but left out vfork because the parent is suspended and cannot race. That no longer holds once vfork is nested. If a vfork child calls vfork again and is then killed with SIGKILL, the parent is released from its vfork wait and runs concurrently with the grandchild in the same mm. Neither of them went through futex_hash_allocate_default(). When both call prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS) at the same time, each one sees mm->futex.phash.ref as NULL and stores its own percpu counter. Only the last store survives. The counter stored first is no longer reachable from the mm, so the references on it are not seen by __futex_ref_atomic_end(). A private hash that still has references is then considered dead and freed, and a task that still holds one of its buckets writes into freed memory in futex_q_lock(). Store the counter once with cmpxchg() and let the loser free_percpu() its own. The initial reference has to be taken before the store, otherwise another task can install a private hash while the counter is still 0.

Why it matters now

EPSS 0.00185 8th percentileScored 2026-11-07

Fix Partial Linux (Linux): 6.18.47, 7.1.11, 7.2.1 +1Red Hat: 3 advisoriesRed Hat: 13 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Linux	Linux	6.17 and later	6.18.47, 7.1.11, 7.2.1, 7.3	Patch available	CNA

Linux VendorLinux Affected 6.17 and later Fixed in 6.18.47, 7.1.11, 7.2.1, 7.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:o:linux:linux_kernel::::::::	—	—	Linux

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

Fix · CNA Linux (Linux) Fixed in 6.18.47, 7.1.11, 7.2.1, 7.3

Red Hat 3 advisories

RHSA-2026:79151 Released 2026-10-20 · Red Hat rating Moderate
OpenShift Container Platform 4.22.18 bug fix and security update
- Red Hat OpenShift Container Platform 4.22 rhcos-aarch64-4.22.9.8.202610061719-0, rhcos-ppc64le-4.22.9.8.202610061719-0, rhcos-s390x-4.22.9.8.202610061719-0 +1
RHSA-2026:76738 Released 2026-10-08 · Red Hat rating Important
kernel security, bug fix, and enhancement update
- 10Base-SMTV kernel-modules-internal-6.12.0-211.63.1.el10_2
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.63.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.63.1.el10_2, kernel-64k-devel-6.12.0-211.63.1.el10_2 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.63.1.el10_2, kernel-64k-6.12.0-211.63.1.el10_2, kernel-64k-core-6.12.0-211.63.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.63.1.el10_2, libperf-6.12.0-211.63.1.el10_2
- Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal-6.12.0-211.63.1.el10_2
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-64k-6.12.0-211.63.1.el10_2, kernel-rt-64k-core-6.12.0-211.63.1.el10_2 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-core-6.12.0-211.63.1.el10_2, kernel-rt-debug-6.12.0-211.63.1.el10_2 +9
RHSA-2026:74438 Released 2026-10-02 · Red Hat rating Moderate
kernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.54.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.54.1.el9_8, kernel-64k-devel-5.14.0-687.54.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.54.1.el9_8, kernel-64k-5.14.0-687.54.1.el9_8, kernel-64k-core-5.14.0-687.54.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.54.1.el9_8, libperf-5.14.0-687.54.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.54.1.el9_8, kernel-rt-64k-5.14.0-687.54.1.el9_8, kernel-rt-64k-core-5.14.0-687.54.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.54.1.el9_8, kernel-rt-core-5.14.0-687.54.1.el9_8, kernel-rt-debug-5.14.0-687.54.1.el9_8 +9

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat OpenShift Container Platform 5	Affected	No fix yet
10Base-SMTV	Fixed	RHSA-2026:76738
Red Hat Enterprise Linux AppStream (v. 10)	Fixed	RHSA-2026:76738
Red Hat Enterprise Linux AppStream (v. 9)	Fixed	RHSA-2026:74438
Red Hat Enterprise Linux BaseOS (v. 10)	Fixed	RHSA-2026:76738
Red Hat Enterprise Linux BaseOS (v. 9)	Fixed	RHSA-2026:74438
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)	Fixed	RHSA-2026:76738
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)	Fixed	RHSA-2026:74438
Red Hat Enterprise Linux Hidden (v. 10)	Fixed	RHSA-2026:76738
Red Hat Enterprise Linux Real Time (v. 10)	Fixed	RHSA-2026:76738
Red Hat Enterprise Linux Real Time (v. 9)	Fixed	RHSA-2026:74438
Red Hat Enterprise Linux Real Time for NFV (v. 10)	Fixed	RHSA-2026:76738
Red Hat Enterprise Linux Real Time for NFV (v. 9)	Fixed	RHSA-2026:74438
Red Hat OpenShift Container Platform 4.22	Fixed	RHSA-2026:79151

Not affected: 5 products

Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8
Red Hat Enterprise Linux 9
Red Hat OpenShift Container Platform 4

Timeline

2026-10-02 Threatist record created from CVE-2026-80775
2026-10-03 Alias added: GHSA-f29q-mg8h-pcrg
2026-10-19 Fix available: Linux/[email protected] · CNA
2026-10-21 Fix available: RHSA-2026:79151 · Red Hat
2026-10-21 Fix available: Red Hat OpenShift Container Platform 4.22 · Red Hat
2026-10-26 Fix available: RHSA-2026:76738 · Red Hat
2026-10-26 Fix available: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) +4 · Red Hat
2026-10-29 Affected versions changed · Red Hat
2026-10-30 Affected versions changed · Red Hat

References

Other 4

TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4

See all 21741 →

Sources

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