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Fencer Vulns
medium 5.5

CVE-2023-53641 json

wifi: ath9k: hif_usb: fix memory leak of remain_skbs

published 2025-10-07 13 mo ago modified 2026-11-05 3 d ago also EUVD-2025-31996

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

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

wifi: ath9k: hif_usb: fix memory leak of remain_skbs

hif_dev->remain_skb is allocated and used exclusively in ath9k_hif_usb_rx_stream(). It is implied that an allocated remain_skb is processed and subsequently freed (in error paths) only during the next call of ath9k_hif_usb_rx_stream().

So, if the urbs are deallocated between those two calls due to the device deinitialization or suspend, it is possible that ath9k_hif_usb_rx_stream() is not called next time and the allocated remain_skb is leaked. Our local Syzkaller instance was able to trigger that.

remain_skb makes sense when receiving two consecutive urbs which are logically linked together, i.e. a specific data field from the first skb indicates a cached skb to be allocated, memcpy'd with some data and subsequently processed in the next call to ath9k_hif_usb_rx_stream(). Urbs deallocation supposedly makes that link irrelevant so we need to free the cached skb in those cases.

Fix the leak by introducing a function to explicitly free remain_skb (if it is not NULL) when the rx urbs have been deallocated. remain_skb is NULL when it has not been allocated at all (hif_dev struct is kzalloced) or when it has been processed in next call to ath9k_hif_usb_rx_stream().

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Patch / fix

  • Linux Linux 4.19.283, 5.4.243, 5.10.180, 5.15.111, 6.1.28, 6.2.15, 6.3.2, 6.4
  • linux Debian 12 6.1.37-1
  • linux Debian 14, Debian 13 6.3.7-1

debian advisories DEBIAN-CVE-2023-53641

  • linux Ubuntu 20.04 LTS 5.4.0-162.179
  • linux Ubuntu 22.04 LTS 5.15.0-79.86
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1109.118
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1042.47
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1112.121
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1039.47
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1039.44
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1056.61

ubuntu advisories UBUNTU-CVE-2023-53641

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 8 4.18.0-513.5.1.el8_9
  • perf RHEL 8 4.18.0-513.5.1.el8_9
  • bpftool RHEL 8 4.18.0-513.5.1.el8_9
  • kernel-core RHEL 8 4.18.0-513.5.1.el8_9
  • kernel-tools RHEL 8 4.18.0-513.5.1.el8_9
  • python3-perf RHEL 8 4.18.0-513.5.1.el8_9
  • kernel-modules RHEL 8 4.18.0-513.5.1.el8_9
  • kernel-zfcpdump RHEL 8 4.18.0-513.5.1.el8_9

red hat advisories RHSA-2023:7077RHSA-2023:6583

  • kernel-64kb SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS, SLE High Performance Computing 15 SP5-ESPOS 5.14.21-150500.55.127.1
  • kernel-syms SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.127.1
  • kernel-source SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.127.1
  • kernel-default SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +3 more 5.14.21-150500.55.127.1
  • kernel-obs-build SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.127.1
  • kernel-default-base SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.127.1.150500.6.61.1
  • kernel-rt SLE Micro 5.5 5.14.21-150500.13.112.1
  • kernel-source-rt SLE Micro 5.5 5.14.21-150500.13.112.1

suse advisories SUSE-SU-2025:4515-1SUSE-SU-2025:4320-1SUSE-SU-2025:4149-1SUSE-SU-2025:4139-1SUSE-SU-2025:4111-1

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-2023-53641 updated cvss 5.5

kernel: wifi: ath9k: hif_usb: fix memory leak of remain_skbs

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +6 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: no fix available “Fix deferred”
  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-513.5.1.el8_9, kernel-debuginfo-common-aarch64 4.18.0-513.5.1.el8_9, kernel-debuginfo-common-ppc64le 4.18.0-513.5.1.el8_9 Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-513.5.1.el8_9, kernel 4.18.0-513.5.1.el8_9, bpftool 4.18.0-513.5.1.el8_9, kernel-core 4.18.0-513.5.1.el8_9, kernel-tools 4.18.0-513.5.1.el8_9, python3-perf 4.18.0-513.5.1.el8_9, +15 more
    fixed: vendor fix RHSA-2023:7077
  • Red Hat Enterprise Linux 10 kernel
    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
partial
Assessed
3 d ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

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

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime
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.