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CVE-2026-98431

N/A

Published 2026-10-14 · Last modified 2026-10-19

In the Linux kernel, the following vulnerability has been resolved: RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency Commit 51976c6cd786 ("RDMA/core: Provide rdma_user_mmap_disassociate() to disassociate mmap pages") introduced disassociation_lock to protect new mmap registrations against uverbs_user_mmap_disassociate(), but created an ABBA deadlock: Thread A (mmap / fork): mmap_lock -> disassociation_lock Thread B (disassociate): disassociation_lock -> mmap_lock Fix by removing disassociation_lock entirely and using the pre-existing hw_destroy_rwsem instead. hw_destroy_rwsem already provides the same protection: rdma_umap_open() and ib_uverbs_mmap() both use down_read_trylock() before registering a new VMA, so holding hw_destroy_rwsem in uverbs_user_mmap_disassociate() is sufficient to block new registrations. trylock is used in both mmap paths (not blocking down_read) because mmap_lock is already held on entry, and uverbs_user_mmap_disassociate() acquires mmap_lock internally — a blocking read would recreate the same deadlock. The only caller that was not taking hw_destroy_rwsem for write was rdma_user_mmap_disassociate(). Fix it to take the rwsem per-ufile while iterating under lists_mutex. This is safe because ib_uverbs_close() releases hw_destroy_rwsem entirely before acquiring lists_mutex, so the two locks are never held simultaneously. lockdep warning: [ 776.654252] ====================================================== [ 776.655214] WARNING: possible circular locking dependency detected [ 776.656167] 6.18.0for-upstream_debug_94e244d9ccab #1 Not tainted [ 776.657114] ------------------------------------------------------ [ 776.658087] devlink/14824 is trying to acquire lock: [ 776.658879] ffff88811170c800 (&mm->mmap_lock){++++}-{4:4}, at: uverbs_user_mmap_disassociate+0x168/0x780 [ib_uverbs] [ 776.660479] [ 776.660479] but task is already holding lock: [ 776.661460] ffff888142d92b08 (&file->disassociation_lock){+.+.}-{4:4}, at: uverbs_user_mmap_disassociate+0x39/0x780 [ib_uverbs] [ 776.663177] [ 776.663177] which lock already depends on the new lock. [ 776.663177] [ 776.664525] [ 776.664525] the existing dependency chain (in reverse order) is: [ 776.665724] [ 776.665724] -> #2 (&file->disassociation_lock){+.+.}-{4:4}: [ 776.666887] __mutex_lock+0x16d/0x2330 [ 776.667633] rdma_umap_open+0x129/0x280 [ib_uverbs] [ 776.668489] dup_mmap+0xa40/0x1790 [ 776.669170] copy_process+0x5dd2/0x6170 [ 776.669933] kernel_clone+0xb6/0x610 [ 776.670636] __do_sys_clone+0xb5/0xf0 [ 776.671354] do_syscall_64+0x70/0x12e0 [ 776.672083] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 776.672940] [ 776.672940] -> #1 (&mm->mmap_lock/1){+.+.}-{4:4}: [ 776.673985] down_write_nested+0x90/0x1e0 [ 776.674751] dup_mmap+0x201/0x1790 [ 776.675448] copy_process+0x5dd2/0x6170 [ 776.676180] kernel_clone+0xb6/0x610 [ 776.676904] __do_sys_clone+0xb5/0xf0 [ 776.677615] do_syscall_64+0x70/0x12e0 [ 776.678351] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 776.679239] [ 776.679239] -> #0 (&mm->mmap_lock){++++}-{4:4}: [ 776.680253] __lock_acquire+0x18c6/0x2ec0 [ 776.681018] lock_acquire+0x10e/0x2e0 [ 776.681742] down_read+0x95/0x430 [ 776.682395] uverbs_user_mmap_disassociate+0x168/0x780 [ib_uverbs] [ 776.683436] uverbs_destroy_ufile_hw+0x1ae/0x270 [ib_uverbs] [ 776.684416] ib_uverbs_remove_one+0x22b/0x420 [ib_uverbs] [ 776.685371] remove_client_context+0xa6/0xf0 [ib_core] [ 776.686342] disable_device+0x12b/0x240 [ib_core] [ 776.687249] __ib_unregister_device+0x269/0x460 [ib_core] [ 776.688233] ib_unregister_device+0x21/0x30 [ib_core] [ 776.689140] mlx5r_remove+0xd0/0x170 [mlx5_ib] [ 776.689999] device_release_driver_internal+0x3b2/0x5 ---truncated---

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 9th percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

—CVSS · not scored

  • No impact metrics

Proof of concept

No public PoC is currently catalogued.

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Data snapshot:

Affected

Vendors Linux

Products Linux

Weakness (CWE)

Not classified.

CVSS vector

Not yet scored.

References and research data (JSON)

Vendor product assessments

Showing 32 of 277 vendor product statements; 245 omitted. Read the full vendor advisory.

  • kernel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-64k-modules-core as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-64k-modules-core

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-devel-matched as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-devel-matched

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-64k-debug-modules as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-64k-debug-modules

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-debug-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-debug-modules-extra

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-zfcpdump-devel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-zfcpdump-devel

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-bootwrapper as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-bootwrapper

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-64k-devel-matched as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-64k-devel-matched

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-debug-modules as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-debug-modules

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-modules-core as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-modules-core

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-64k-debug-modules-core as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-64k-debug-modules-core

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-debug-core as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-debug-core

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-modules-core as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-modules-core

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-zfcpdump-devel-matched as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-zfcpdump-devel-matched

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · known affected

    Vendor assessment for this product only.

    pkg:oci/ose-rhel-coreos-9?repository_url=registry.redhat.io/openshift/ose-rhel-coreos-9

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • bpftool as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/bpftool

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-debug-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-debug-devel

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-kdump-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-kdump-devel

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-doc as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-doc

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt.src as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt?arch=src

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • perf as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/perf

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-abi-whitelists as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-abi-whitelists

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-debug-devel as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-debug-devel

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-headers as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-headers

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-debug-kvm as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-debug-kvm

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt-kvm as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-kvm

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-rt.src as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt?arch=src

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel-zfcpdump-core as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-zfcpdump-core

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • kernel.src as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel?arch=src

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00
  • openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/ose-rhel-coreos-8?repository_url=registry.redhat.io/openshift/ose-rhel-coreos-8

    Red Hat · CVE-2026-98431 · Updated 2026-10-18T08:33:45+00:00

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS