CVE-2025-38086: Linux kernel · net: ch9200: fix uninitialised access during mii_nway_restart
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1092.99~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 16:39 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1092.99~20.04.1, 5.15.0-1096.105~20.04.1, 5.15.0-1092.101~20.04.1 +63
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.
Patches and advisories
- ubuntu.com/security/notices/USN-7774-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7776-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7834-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-2 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
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: net: ch9200: fix uninitialised access during mii_nway_restart In mii_nway_restart() the code attempts to call mii->mdio_read which is ch9200_mdio_read(). ch9200_mdio_read() utilises a local buffer called "buff", which is initialised with control_read(). However "buff" is conditionally initialised inside control_read(): if (err == size) { memcpy(data, buf, size); } If the condition of "err == size" is not met, then "buff" remains uninitialised. Once this happens the uninitialised "buff" is accessed and returned during ch9200_mdio_read(): return (buff[0] | buff[1] << 8); The problem stems from the fact that ch9200_mdio_read() ignores the return value of control_read(), leading to uinit-access of "buff". To fix this we should check the return value of control_read() and return early on error.
References
- ubuntu.com/security/CVE-2025-38086 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-38086 (opens in a new tab)
- git.kernel.org/linus/9ad0452c0277b816a435433cca601304cfac7c21 (opens in a new tab)
- git.kernel.org/stable/c/119766de4930ff40db9f36b960cb53b0c400e81b (opens in a new tab)
- git.kernel.org/stable/c/33163c68d2e3061fa3935b5f0a1867958b1cdbd2 (opens in a new tab)
- git.kernel.org/stable/c/4da7fcc098218ff92b2e83a43f545c02f714cedd (opens in a new tab)
- git.kernel.org/stable/c/6bd2569d0b2f918e9581f744df0263caf73ee76c (opens in a new tab)
- git.kernel.org/stable/c/9a350f30d65197354706b7759b5c89d6c267b1a9 (opens in a new tab)
- git.kernel.org/stable/c/9ad0452c0277b816a435433cca601304cfac7c21 (opens in a new tab)
- git.kernel.org/stable/c/9da3e442714f7f4393ff01c265c4959c03e88c2f (opens in a new tab)
- git.kernel.org/stable/c/cdaa6d1cb2ff1219c6c822b27655dd170ffb0f72 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7776-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-5 (opens in a new tab)