CVE-2025-21915: Linux kernel · cdx: Fix possible UAF error in driver_override_show()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1039.41~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1039.41~22.04.1, 6.8.0-1036.42~22.04.1, 6.8.0-1040.42~22.04.1 +34
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 Apr 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.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-84.84?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1039.41?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1038.44?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11@6.11.0-1018.18~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia@6.8.0-1025.27?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp@6.8.0-1040.42?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: cdx: Fix possible UAF error in driver_override_show() Fixed a possible UAF problem in driver_override_show() in drivers/cdx/cdx.c This function driver_override_show() is part of DEVICE_ATTR_RW, which includes both driver_override_show() and driver_override_store(). These functions can be executed concurrently in sysfs. The driver_override_store() function uses driver_set_override() to update the driver_override value, and driver_set_override() internally locks the device (device_lock(dev)). If driver_override_show() reads cdx_dev->driver_override without locking, it could potentially access a freed pointer if driver_override_store() frees the string concurrently. This could lead to printing a kernel address, which is a security risk since DEVICE_ATTR can be read by all users. Additionally, a similar pattern is used in drivers/amba/bus.c, as well as many other bus drivers, where device_lock() is taken in the show function, and it has been working without issues. This potential bug was detected by our experimental static analysis tool, which analyzes locking APIs and paired functions to identify data races and atomicity violations.
References
- ubuntu.com/security/CVE-2025-21915 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21915 (opens in a new tab)
- git.kernel.org/linus/91d44c1afc61a2fec37a9c7a3485368309391e0b (opens in a new tab)
- ubuntu.com/security/notices/USN-7605-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7606-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7605-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7628-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7764-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7765-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7766-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7767-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7779-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7767-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7764-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7790-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7801-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7802-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7801-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7809-1 (opens in a new tab)