CVE-2025-39992: Linux kernel · mm: swap: check for stable address space before operating on the VMA
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 6.8.0-1050.53~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- 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 6.8.0-1050.53~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1052.55~22.04.1 +32
Exploitation evidence
Disclosed: evidence found.
CVE published 15 Oct 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 25.10linuxpkg:deb/ubuntu/linux@6.17.0-6.6?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1003.3?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1006.6?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1003.3?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1003.3?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected Linux kernel versions. The vendor advisory from Ubuntu confirms that this and other kernel vulnerabilities have been fixed in updated kernel packages. Users should update to the fixed kernel versions as provided by their Linux distribution. No additional mitigations are specified or required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's memory management subsystem involving swapoff and virtual memory area (VMA) handling has been resolved. The flaw arises from a race condition between fork() and swapoff operations, leading to a kernel NULL pointer dereference (OOPS) when unuse_mm() encounters a zero entry marker (XA_ZERO_ENTRY) in the VMA list. This occurs because a partially initialized memory descriptor (mm_struct) is exposed during duplication, causing unsafe access. The issue has been fixed by ensuring stable address space checks before operating on VMAs and preventing exposure of partially valid memory trees.
References
- ubuntu.com/security/CVE-2025-39992 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39992 (opens in a new tab)
- git.kernel.org/linus/1367da7eb875d01102d2ed18654b24d261ff5393 (opens in a new tab)
- git.kernel.org/stable/c/1367da7eb875d01102d2ed18654b24d261ff5393 (opens in a new tab)
- git.kernel.org/stable/c/4e5f060d7347466f77aaff1c0d5a6c4f1fb217ac (opens in a new tab)
- git.kernel.org/stable/c/9cddad3b26dac830407d2d3c0de5205ff6d6dda0 (opens in a new tab)
- git.kernel.org/stable/c/e4e99d69b8b8295c501b2eef89e13306b738b667 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8125-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8126-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8165-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8261-1 (opens in a new tab)