CVE-2025-68810: Linux kernel · KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1052.55~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1052.55~22.04.1, 6.8.0-1059.65~22.04.1, 6.8.0-1054.57~22.04.1 +40
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 13 Jan 2026
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@6.17.0-22.22?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1012.12?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1013.13?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@6.17.0-1012.12?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1011.11?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
An official patch is available and should be applied to affected Linux kernel versions. The fix disallows toggling the KVM_MEM_GUEST_MEMFD flag on existing memslots, preventing the use-after-free condition. Users should update their Linux kernel to a patched version and reboot to apply the fix. No additional mitigations are specified or required beyond applying the official update.
Description
A use-after-free vulnerability in the Linux kernel's KVM subsystem was resolved by disallowing toggling the KVM_MEM_GUEST_MEMFD flag on existing memory slots. The flaw allowed clearing this flag on memslots initially created with guest_memfd binding, which KVM does not support, leading to a use-after-free condition. This vulnerability has a CVSS score of 7.8 and affects multiple Linux kernel versions. An official fix is available and should be applied.
References
- ubuntu.com/security/CVE-2025-68810 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-68810 (opens in a new tab)
- git.kernel.org/linus/9935df5333aa503a18de5071f53762b65c783c4c (opens in a new tab)
- git.kernel.org/stable/c/89dbbe6ff323fc34659621a577fe0af913f47386 (opens in a new tab)
- git.kernel.org/stable/c/9935df5333aa503a18de5071f53762b65c783c4c (opens in a new tab)
- git.kernel.org/stable/c/cb51bef465d8ec60a968507330e01020e35dc127 (opens in a new tab)
- ubuntu.com/security/notices/USN-8177-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8177-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8183-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8184-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8185-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8183-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8203-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8204-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8185-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8245-1 (opens in a new tab)