CVE-2026-93121: Linux kernel · usb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.0 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 17 Sep 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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 fix is available that corrects the cleanup logic in the ffs_dmabuf_transfer() function by replacing dma_fence_put() with kfree() in the relevant error paths. Users should apply the official Linux kernel updates that include this patch to resolve the vulnerability.
Description
A vulnerability in the Linux kernel's USB gadget function f_fs was resolved involving improper cleanup of a dma_fence object in error paths of ffs_dmabuf_transfer(). The issue occurs because dma_fence_put() is called on a fence object that has only been allocated but not fully initialized, leading to undefined behavior. The fix changes the cleanup to use kfree() instead of dma_fence_put() in these error paths.
References
- nvd.nist.gov/vuln/detail/CVE-2026-93121 (opens in a new tab)
- git.kernel.org/stable/c/58952c83dfe6ea3294a74734d2d1018c1120779a (opens in a new tab)
- git.kernel.org/stable/c/5fd8baacc7dc477df9cac61b45491840247a9b1e (opens in a new tab)
- git.kernel.org/stable/c/621707dc67c9846fd876d7579ec951d92aa033f1 (opens in a new tab)
- git.kernel.org/stable/c/be539138d9a187af3b884525a395db10797c64f1 (opens in a new tab)
- ubuntu.com/security/CVE-2026-93121 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-93121 (opens in a new tab)
- git.kernel.org/linus/621707dc67c9846fd876d7579ec951d92aa033f1 (opens in a new tab)