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Full vulnerability report · 2025
CVE-2023-53641High confidence

wifi: ath9k: hif_usb: fix memory leak of remain_skbs

Linux · Linux

5.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

9 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivelinux-azure-6.11Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gcp-6.11Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-hwe-6.11Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-intelAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-lowlatency-hwe-6.11Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oem-6.11Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspi-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-riscvAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-31996

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

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.

What

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.

Why

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Missing Release of Memory after Effective Lifetime → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-401

CWE-401: Missing Release of Memory after Effective Lifetime. The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-401
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2026-0349Dell Avamar und NetWorker: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Dell Avamar und Dell NetWorker ausnutzen, um Angriffe zu starten, die die Integrität, Vertraulichkeit und Verfügbarkeit von Systemen beeinträchtigen.

Official advisory
BSI · German · WID-SEC-W-2025-2229Linux Kernel: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service Angriff durchzuführen und andere nicht näher spezifizierte Angriffe durchzuführen.

Official advisory
CERT-FR · French · CERTFR-2025-AVI-1140Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2022-50545 Référence CVE CVE-2022-50551 https://www.cve.org/CVERecord?id=CVE-2022-50551 Référence CVE CVE-2022-50569 https://www.cve.org/CVERecord?id=CVE-2022-50569 Référence CVE CVE-2022-50578 https://www.cve.org/CVERecord?id=CVE-2022-50578 Référence CVE CVE-2023-53229 https://www.cve.org/CVERecord?id=CVE-2023-53229 Référence CVE CVE-2023-53369 https://www.cve.org/CVERecord?id=CVE-2023-53369 Référence CVE CVE-2023-53431 https://www.cve.org/CVERecord?id=CVE-2023-53431 Référence CVE CVE-2023-53542 https://www.cve.org/CVERecord?id=CVE-2023-53542 Référence CVE CVE-2023-53597 https://www.cve.org/CVERecord?id=CVE-2023-53597 Référence CVE CVE-2023-53641 https://www.cve.org/CVERecord?id=CVE-2023-53641 Référence CVE CVE-2023-53676 https://www.cve.org/CVERecord?id=CVE-2023-53676 Référence CVE CVE-2024-53093 https://www.cve.org/CVERecord?id=CVE-2024-53093 Référence CVE CVE-2025-21710 https://www.cve.org/CVERecord?id=CVE-2025-21710 Référence CVE CVE-2025-37916 https://www.cve.org/CVERecord?id=CVE-2025-37916 Référence CVE CVE-2025-38359 https://www.cve.org/CVERecord?id=CVE-2025-38359 Référence CVE CVE-2025-38360 https://www.cve.org/CVERecord?id=CVE-2025-38360 Référence CVE CVE-2025-38361 https://www.cve.org/CVERecord?id=CVE-2025-38361 Référence CVE CVE-2025-38436 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2025-AVI-1073Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2023-53625 Référence CVE CVE-2023-53626 https://www.cve.org/CVERecord?id=CVE-2023-53626 Référence CVE CVE-2023-53631 https://www.cve.org/CVERecord?id=CVE-2023-53631 Référence CVE CVE-2023-53632 https://www.cve.org/CVERecord?id=CVE-2023-53632 Référence CVE CVE-2023-53633 https://www.cve.org/CVERecord?id=CVE-2023-53633 Référence CVE CVE-2023-53637 https://www.cve.org/CVERecord?id=CVE-2023-53637 Référence CVE CVE-2023-53638 https://www.cve.org/CVERecord?id=CVE-2023-53638 Référence CVE CVE-2023-53639 https://www.cve.org/CVERecord?id=CVE-2023-53639 Référence CVE CVE-2023-53640 https://www.cve.org/CVERecord?id=CVE-2023-53640 Référence CVE CVE-2023-53641 https://www.cve.org/CVERecord?id=CVE-2023-53641 Référence CVE CVE-2023-53644 https://www.cve.org/CVERecord?id=CVE-2023-53644 Référence CVE CVE-2023-53645 https://www.cve.org/CVERecord?id=CVE-2023-53645 Référence CVE CVE-2023-53646 https://www.cve.org/CVERecord?id=CVE-2023-53646 Référence CVE CVE-2023-53647 https://www.cve.org/CVERecord?id=CVE-2023-53647 Référence CVE CVE-2023-53648 https://www.cve.org/CVERecord?id=CVE-2023-53648 Référence CVE CVE-2023-53649 https://www.cve.org/CVERecord?id=CVE-2023-53649 Référence CVE CVE-2023-53650 https://www.cve.org/CVERecord?id=CVE-2023-53650 Référence CVE CVE-2023-53651 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2025-AVI-1032Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2023-53625 Référence CVE CVE-2023-53626 https://www.cve.org/CVERecord?id=CVE-2023-53626 Référence CVE CVE-2023-53631 https://www.cve.org/CVERecord?id=CVE-2023-53631 Référence CVE CVE-2023-53632 https://www.cve.org/CVERecord?id=CVE-2023-53632 Référence CVE CVE-2023-53633 https://www.cve.org/CVERecord?id=CVE-2023-53633 Référence CVE CVE-2023-53637 https://www.cve.org/CVERecord?id=CVE-2023-53637 Référence CVE CVE-2023-53638 https://www.cve.org/CVERecord?id=CVE-2023-53638 Référence CVE CVE-2023-53639 https://www.cve.org/CVERecord?id=CVE-2023-53639 Référence CVE CVE-2023-53640 https://www.cve.org/CVERecord?id=CVE-2023-53640 Référence CVE CVE-2023-53641 https://www.cve.org/CVERecord?id=CVE-2023-53641 Référence CVE CVE-2023-53644 https://www.cve.org/CVERecord?id=CVE-2023-53644 Référence CVE CVE-2023-53645 https://www.cve.org/CVERecord?id=CVE-2023-53645 Référence CVE CVE-2023-53646 https://www.cve.org/CVERecord?id=CVE-2023-53646 Référence CVE CVE-2023-53647 https://www.cve.org/CVERecord?id=CVE-2023-53647 Référence CVE CVE-2023-53648 https://www.cve.org/CVERecord?id=CVE-2023-53648 Référence CVE CVE-2023-53649 https://www.cve.org/CVERecord?id=CVE-2023-53649 Référence CVE CVE-2023-53650 https://www.cve.org/CVERecord?id=CVE-2023-53650 Référence CVE CVE-2023-53651 https://www.cve.org/CVERecord?id=

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
fb9987d0f748c983bb795a86f47522313f701a08 < 6719e3797ec52cd144c8a5ba8aaab36674800585; fb9987d0f748c983bb795a86f47522313f701a08 < d9899318660791141ea6002fda5577b2c5d7386e; fb9987d0f748c983bb795a86f47522313f701a08 < 320d760a35273aa815d58b57e4fd9ba5279a3489; fb9987d0f748c983bb795a86f47522313f701a08 < 59073060fe0950c6ecbe12bdc06469dcac62128d; fb9987d0f748c983bb795a86f47522313f701a08 < 9b9356a3014123f0ce4b50d9278c1265173150ab; fb9987d0f748c983bb795a86f47522313f701a08 < f0931fc8f4b6847c72e170d2326861c0a081d680; fb9987d0f748c983bb795a86f47522313f701a08 < 8f02d538878c9b1501f624595eb22ee4e5e0ff84; fb9987d0f748c983bb795a86f47522313f701a08 < 7654cc03eb699297130b693ec34e25f77b17c947
Fixed
< 2.6.35; 4.19.283 ≤ 4.19.*; 5.4.243 ≤ 5.4.*; 5.10.180 ≤ 5.10.*; 5.15.111 ≤ 5.15.*; 6.1.28 ≤ 6.1.*; 6.2.15 ≤ 6.2.*; 6.3.2 ≤ 6.3.*
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 7 Oct 2025 · Last source change 11 May 2026, 19:49 UTC · CWE-401 · Missing Release of Memory after Effective Lifetime

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-31996
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-53641 · cve.blacktree.nl