CVE-2025-39698: Linux kernel · io_uring/futex: ensure io_futex_wait() cleans up properly on failure
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High · fixed in 6.8.0-1045.47~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% 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 6.8.0-1045.47~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1046.49~22.04.1 +26
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 5 Sep 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-8015-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8016-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8074-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8074-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8126-1 (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: io_uring/futex: ensure io_futex_wait() cleans up properly on failure The io_futex_data is allocated upfront and assigned to the io_kiocb async_data field, but the request isn't marked with REQ_F_ASYNC_DATA at that point. Those two should always go together, as the flag tells io_uring whether the field is valid or not. Additionally, on failure cleanup, the futex handler frees the data but does not clear ->async_data. Clear the data and the flag in the error path as well. Thanks to Trend Micro Zero Day Initiative and particularly ReDress for reporting this.
References
- ubuntu.com/security/CVE-2025-39698 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39698 (opens in a new tab)
- git.kernel.org/linus/508c1314b342b78591f51c4b5dadee31a88335df (opens in a new tab)
- git.kernel.org/stable/c/508c1314b342b78591f51c4b5dadee31a88335df (opens in a new tab)
- git.kernel.org/stable/c/d34c04152df517c59979b4bf2a47f491e06d3256 (opens in a new tab)
- git.kernel.org/stable/c/d9f93172820a53ab42c4b0e5e65291f4f9d00ad2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8016-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8015-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8074-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8074-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8126-1 (opens in a new tab)