CVE-2025-38736 — net: usb: asix_devices: Fix PHY address mask in MDIO bus initialization
In the Linux kernel, the following vulnerability has been resolved: net: usb: asix_devices: Fix PHY address mask in MDIO bus initialization Syzbot reported shift-out-of-bounds exception on MDIO bus initialization. The PHY address should be masked to 5 bits (0-31). Without this mask, invalid PHY addresses could be used, potentially causing issues with MDIO bus operations. Fix this by masking the PHY address with 0x1f (31 decimal) to ensure it stays within the valid range.
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 0.2% (30-day exploitation probability)+1
- Technical severity (high)+6
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)
- 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 (Debian Debian Linux, 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 |
|---|---|---|---|---|
| Debian | Debian Linux | version 11.0 | Vulnerable | NIST National Vulnerability Database |
| Linux | Linux |
≥ 75947d3200de98a9ded9ad8972e02f1a177097fe and < fcb4ce9f729c1d08e53abf9d449340e24c3edee6≥ 59ed6fbdb1bc03316e09493ffde7066f031c7524 and < 8f141f2a4f2ef8ca865d5921574c3d6535e00a49≥ ccef5ee4adf56472aa26bdd1f821a6d0cd06089a and < 748da80831221ae24b4bc8d7ffb22acd5712a341≥ ee2cd40b0bb46056949a2319084a729d95389386 and < 22042ffedd8c2c6db08ccdd6d4273068eddd3c5c≥ ad1f8313aeec0115f9978bd2d002ef4a8d96c773 and < 523eab02fce458fa6d3c51de5bb055800986953e≥ 4faff70959d51078f9ee8372f8cff0d7045e4114 and < 24ef2f53c07f273bad99173e27ee88d44d135b1cversion a754ab53993b1585132e871c5d811167ad3c52ff≥ 6.15.11 and < 6.16 and 2 more≥ 6.12.43 and < 6.12.44≥ 6.16.2 and < 6.16.4 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel | ≥ 6.15.11 and < 6.16≥ 6.16.2 and < 6.16.4version 6.12.43version 6.17-rc2 | 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 |
|---|---|---|---|---|---|
| 7.1 | CVSS 3.1 | High | 1.8 | 5.2 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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
- CVSS changed · 7.1
- Source status changed · → Modified
- Record created in this database
- 2025
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
10 on the record
- git.kernel.org/stable/c/fcb4ce9f729c1d08e53abf9d449340e24c3edee6
- git.kernel.org/stable/c/8f141f2a4f2ef8ca865d5921574c3d6535e00a49
- git.kernel.org/stable/c/22042ffedd8c2c6db08ccdd6d4273068eddd3c5c
- git.kernel.org/stable/c/24ef2f53c07f273bad99173e27ee88d44d135b1c
- git.kernel.org/stable/c/748da80831221ae24b4bc8d7ffb22acd5712a341
- git.kernel.org/stable/c/523eab02fce458fa6d3c51de5bb055800986953e
- cert-portal.siemens.com/productcert/html/ssa-032379.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- lists.debian.org/debian-lts-announce/2025/10/msg00008.html
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 8h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 8h
- 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-2025-38736 is "net: usb: asix_devices: Fix PHY address mask in MDIO bus initialization", rated High. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.1 describes technical severity. EPSS 0.17% 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.
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