CVE-2025-21744 — wifi: brcmfmac: fix NULL pointer dereference in brcmf_txfinalize()
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.3% (30-day exploitation probability)+2
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < 3877fc67bd3d5566cc12763bce39710ceb74a97dversion 4.9≥ 4.8.4 and < 4.9≥ 4.7.10 and < 4.8version 9119232cc92a269d7860b4aa51f07d3923a3cc10version 6faa698c35a43b9e74ea24e90fe37471d08d00d0≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < 68abd0c4ebf24cd499841a488b97a6873d5efabb≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < a2beefc4fa49ebc22e664dc6b39dbd054f8488f9 and 5 more≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < fbbfef2a5b858eab55741a58b2ac9a0cc8d53c58≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < 4e51d6d093e763348916e69d06d87e0a5593661b≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < 61541d9b5a23df33934fcc620a3a81f246b1b240≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < 59ff4fa653ff6db07c61152516ffba79c2a74bda≥ 7f00ee2bbc630900ba16fc2690473f3e2db0e264 and < 2326e19190e176fd72bb542b837a9d2b7fcb8693 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel | < 6.1.129≥ 6.13 and < 6.13.3≥ 6.7 and < 6.12.14≥ 6.2 and < 6.6.78 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.5 | CVSS 3.1 | Medium | 1.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
| 5.5 | CVSS 3.1 | Medium | — | — | GitHub, Inc. via GitHub Security Advisories |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- Affected products added · linux/linux kernel
- CVSS changed · 5.5
- Source status changed · → Modified
- Record created in this database
- 2025
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 14, 2026 – Oct 14, 2026
References
14 on the record
- git.kernel.org/stable/c/a2beefc4fa49ebc22e664dc6b39dbd054f8488f9
- git.kernel.org/stable/c/4e51d6d093e763348916e69d06d87e0a5593661b
- git.kernel.org/stable/c/3877fc67bd3d5566cc12763bce39710ceb74a97d
- git.kernel.org/stable/c/68abd0c4ebf24cd499841a488b97a6873d5efabb
- git.kernel.org/stable/c/fbbfef2a5b858eab55741a58b2ac9a0cc8d53c58
- nvd.nist.gov/vuln/detail/CVE-2025-21744
- github.com/advisories/GHSA-xqj4-x748-chwg
- lists.debian.org/debian-lts-announce/2025/05/msg00030.html
- git.kernel.org/stable/c/61541d9b5a23df33934fcc620a3a81f246b1b240
- cert-portal.siemens.com/productcert/html/ssa-784472.html
- git.kernel.org/stable/c/59ff4fa653ff6db07c61152516ffba79c2a74bda
- lists.debian.org/debian-lts-announce/2025/03/msg00028.html
- git.kernel.org/stable/c/2326e19190e176fd72bb542b837a9d2b7fcb8693
- cert-portal.siemens.com/productcert/html/ssa-265688.html
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 13h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 13h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2025-21744 is "wifi: brcmfmac: fix NULL pointer dereference in brcmf_txfinalize()", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 0.25% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.