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Fencer Vulns
high 8.8

CVE-2025-39698 json

io_uring/futex: ensure io_futex_wait() cleans up properly on failure

published 2025-09-05 14 mo ago modified 2026-10-19 20 d ago also EUVD-2025-31205

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

io_uring/futex: ensure io_futex_wait() cleans up properly on failure

The io_futex_data is allocated upfront and assigned to the io_kiocb async_data field, but the request isn't marked with REQ_F_ASYNC_DATA at that point. Those two should always go together, as the flag tells io_uring whether the field is valid or not.

Additionally, on failure cleanup, the futex handler frees the data but does not clear ->async_data. Clear the data and the flag in the error path as well.

Thanks to Trend Micro Zero Day Initiative and particularly ReDress for reporting this.

Patch / fix

  • Linux Linux 6.12.44, 6.16.4, 6.17
  • linux Debian 13 6.12.48-1
  • linux Debian 14 6.16.5-1

debian advisories DEBIAN-CVE-2025-39698

  • linux Ubuntu 24.04 LTS 6.8.0-94.96
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1045.47
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1046.49
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1042.47
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1043.43
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1046.52
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1029.32
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1045.49

ubuntu advisories UBUNTU-CVE-2025-39698

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.0 6.12.0-55.37.1.el10_0
  • rv RHEL 10.0 6.12.0-55.37.1.el10_0
  • perf RHEL 10.0 6.12.0-55.37.1.el10_0
  • rtla RHEL 10.0 6.12.0-55.37.1.el10_0
  • libperf RHEL 10.0 6.12.0-55.37.1.el10_0
  • kernel-rt RHEL 10.0 6.12.0-55.37.1.el10_0
  • kernel-64k RHEL 10.0 6.12.0-55.37.1.el10_0
  • kernel-core RHEL 10.0 6.12.0-55.37.1.el10_0

red hat advisories RHSA-2025:16904RHSA-2025:16880

  • kernel-livepatch-SLE16-RT_Update_0 Linux Micro 6.2 5-160000.3.4
  • kernel-livepatch-SLE16_Update_0 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 7-160000.4.3
  • kernel-rt Linux Micro 6.2 6.12.0-160000.6.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.6.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1.160000.2.4
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1

suse advisories SUSE-SU-2026:20645-1SUSE-SU-2026:20635-1SUSE-SU-2026:20644-1SUSE-SU-2025:21074-1SUSE-SU-2025:21139-1SUSE-SU-2026:20560-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.6.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.6.1

opensuse advisories openSUSE-SU-2025:20081-1

  • kernel AlmaLinux 9 5.14.0-570.49.1.el9_6
  • rv AlmaLinux 9 5.14.0-570.49.1.el9_6
  • perf AlmaLinux 9 5.14.0-570.49.1.el9_6
  • rtla AlmaLinux 9 5.14.0-570.49.1.el9_6
  • libperf AlmaLinux 9 5.14.0-570.49.1.el9_6
  • kernel-rt AlmaLinux 9 5.14.0-570.49.1.el9_6
  • kernel-64k AlmaLinux 9 5.14.0-570.49.1.el9_6
  • kernel-core AlmaLinux 9 5.14.0-570.49.1.el9_6

almalinux advisories ALSA-2025:16880ALSA-2025:16904

  • kernel Rocky Linux 9 5.14.0-570.49.1.el9_6
  • kernel Rocky Linux 10 6.12.0-55.37.1.el10_0

rocky linux advisories RLSA-2025:16880RLSA-2025:16904

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-39698 updated cvss 7.3

kernel: io_uring/futex: ensure io_futex_wait() cleans up properly on failure

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-570.49.1.el9_6, perf 5.14.0-570.49.1.el9_6, rtla 5.14.0-570.49.1.el9_6, python3-perf 5.14.0-570.49.1.el9_6, kernel-devel-matched 5.14.0-570.49.1.el9_6, kernel-64k-devel-matched 5.14.0-570.49.1.el9_6, +7 more
    fixed: vendor fix RHSA-2025:16880
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-55.37.1.el10_0, perf 6.12.0-55.37.1.el10_0, rtla 6.12.0-55.37.1.el10_0, python3-perf 6.12.0-55.37.1.el10_0, kernel-devel-matched 6.12.0-55.37.1.el10_0, kernel-64k-devel-matched 6.12.0-55.37.1.el10_0, +7 more
    fixed: vendor fix RHSA-2025:16904
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-570.49.1.el9_6, kernel-64k 5.14.0-570.49.1.el9_6, kernel-core 5.14.0-570.49.1.el9_6, kernel-tools 5.14.0-570.49.1.el9_6, kernel-modules 5.14.0-570.49.1.el9_6, kernel-64k-core 5.14.0-570.49.1.el9_6, +27 more
    fixed: vendor fix RHSA-2025:16880
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-55.37.1.el10_0, kernel-64k 6.12.0-55.37.1.el10_0, kernel-core 6.12.0-55.37.1.el10_0, kernel-tools 6.12.0-55.37.1.el10_0, kernel-modules 6.12.0-55.37.1.el10_0, kernel-64k-core 6.12.0-55.37.1.el10_0, +27 more
    fixed: vendor fix RHSA-2025:16904
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-570.49.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.49.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.49.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.49.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.49.1.el9_6
    fixed: vendor fix RHSA-2025:16880
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-55.37.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.37.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.37.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.37.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.37.1.el10_0
    fixed: vendor fix RHSA-2025:16904
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-570.49.1.el9_6, kernel-rt-64k 5.14.0-570.49.1.el9_6, kernel-rt-core 5.14.0-570.49.1.el9_6, kernel-rt-modules 5.14.0-570.49.1.el9_6, kernel-rt-64k-core 5.14.0-570.49.1.el9_6, kernel-rt-debug-core 5.14.0-570.49.1.el9_6, +14 more
    fixed: vendor fix RHSA-2025:16880
show 4 more
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-55.37.1.el10_0, kernel-rt-64k 6.12.0-55.37.1.el10_0, kernel-rt-core 6.12.0-55.37.1.el10_0, kernel-rt-modules 6.12.0-55.37.1.el10_0, kernel-rt-64k-core 6.12.0-55.37.1.el10_0, kernel-rt-debug-core 6.12.0-55.37.1.el10_0, +14 more
    fixed: vendor fix RHSA-2025:16904
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-570.49.1.el9_6, kernel-rt-kvm 5.14.0-570.49.1.el9_6, kernel-rt-core 5.14.0-570.49.1.el9_6, kernel-rt-modules 5.14.0-570.49.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.49.1.el9_6, kernel-rt-debug-core 5.14.0-570.49.1.el9_6, +6 more
    fixed: vendor fix RHSA-2025:16880
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-55.37.1.el10_0, kernel-rt-kvm 6.12.0-55.37.1.el10_0, kernel-rt-core 6.12.0-55.37.1.el10_0, kernel-rt-modules 6.12.0-55.37.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.37.1.el10_0, kernel-rt-debug-core 6.12.0-55.37.1.el10_0, +6 more
    fixed: vendor fix RHSA-2025:16904
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
13 mo ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CISA ADP 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-672 Operation on a Resource after Expiration or Release
  • CWE-416 Use After Free
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.