CVE-2026-99039: Linux kernel · memstick: core: wait for request completion before freeing card
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 28 Oct 2026, 01:44 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 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 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther 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 replaces wait_for_completion_timeout() with wait_for_completion() in memstick_alloc_card() and memstick_set_rw_addr(), ensuring the card structure is not freed while asynchronous requests are in flight. Users should apply the updated Linux kernel versions containing this fix. No additional mitigations are indicated.
Description
A use-after-free vulnerability exists in the Linux kernel memstick subsystem where asynchronous requests may write to memory after the associated card structure has been freed. This occurs because wait_for_completion_timeout() is used to wait for request completion, and if it times out, the card structure is freed while the request is still in flight. The issue is fixed by replacing wait_for_completion_timeout() with wait_for_completion() to ensure the card is not freed prematurely.
References
- ubuntu.com/security/CVE-2026-99039 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99039 (opens in a new tab)
- git.kernel.org/stable/c/3af81770e2011c6ac7bb597a4af2e4f3591f928c (opens in a new tab)
- git.kernel.org/stable/c/810580cf60edc75c9891c2de3225e4cda78e4d9f (opens in a new tab)
- git.kernel.org/stable/c/aa0a37b5024d921e96ac4f8f487c8bfbf1f1a582 (opens in a new tab)
- git.kernel.org/stable/c/c3ab92542475d59ae685cbb294e70ca4d0ba38e9 (opens in a new tab)
- git.kernel.org/stable/c/f2795c50144d528dabc2cf2fd53c0f0c63a823a1 (opens in a new tab)