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VulnerabilityPublished Updated

CVE-2025-21744: Linux kernel · wifi: brcmfmac: fix NULL pointer dereference in brcmf_txfinalize()

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 5.5 Medium · fixed in 5.4.0-1146.156~18.04.1 : update Linux kernel when convenient.

Data as of 28 Oct 2026, 11:14 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.4.0-1146.156~18.04.1, 5.4.0-1151.158~18.04.1, 5.4.0-1149.158~18.04.1 +85
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Feb 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-64.67
Fixed in
  • 6.8.0-64.67
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1032.34
Fixed in
  • 6.8.0-1032.34
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1034.39
Fixed in
  • 6.8.0-1034.39
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • <6.11.0-1015.15~24.04.1
Fixed in
  • 6.11.0-1015.15~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1022.23
Fixed in
  • 6.8.0-1022.23
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1033.35
Fixed in
  • 6.8.0-1033.35

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix NULL pointer dereference in brcmf_txfinalize() On removal of the device or unloading of the kernel module a potential NULL pointer dereference occurs. The following sequence deletes the interface: brcmf_detach() brcmf_remove_interface() brcmf_del_if() Inside the brcmf_del_if() function the drvr->if2bss[ifidx] is updated to BRCMF_BSSIDX_INVALID (-1) if the bsscfgidx matches. After brcmf_remove_interface() call the brcmf_proto_detach() function is called providing the following sequence: brcmf_detach() brcmf_proto_detach() brcmf_proto_msgbuf_detach() brcmf_flowring_detach() brcmf_msgbuf_delete_flowring() brcmf_msgbuf_remove_flowring() brcmf_flowring_delete() brcmf_get_ifp() brcmf_txfinalize() Since brcmf_get_ip() can and actually will return NULL in this case the call to brcmf_txfinalize() will result in a NULL pointer dereference inside brcmf_txfinalize() when trying to update ifp->ndev->stats.tx_errors. This will only happen if a flowring still has an skb. Although the NULL pointer dereference has only been seen when trying to update the tx statistic, all other uses of the ifp pointer have been guarded as well with an early return if ifp is NULL.

References

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