CVE-2026-99016: Linux kernel · riscv: futex: untag the user pointer before the atomic access
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 28 Oct 2026, 01:44 UTC
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 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 for this vulnerability has been implemented in the Linux kernel by untagging the user pointer before performing atomic operations in the futex code, aligning with the access_ok() validation. Users should apply the updated kernel versions that include this fix. The affected versions are explicitly listed and should be upgraded to patched releases. No additional mitigations are indicated beyond applying the official fix.
Description
CVE-2026-99016 is a vulnerability in the Linux kernel's RISC-V futex implementation where the user pointer is not properly untagged before atomic operations. This can allow an unprivileged process to perform atomic read-modify-write operations on arbitrary kernel memory addresses, potentially leading to high impact including confidentiality, integrity, and availability violations. The issue arises due to a mismatch between the pointer checked by access_ok() and the pointer used in atomic operations when tagged address ABI is enabled. The vulnerability affects specific Linux kernel versions listed and has a CVSS score of 7.8 (high severity).
References
- ubuntu.com/security/CVE-2026-99016 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99016 (opens in a new tab)
- git.kernel.org/stable/c/2e5c80bbc062a8dda33e687ebf7be8f074ee4f7d (opens in a new tab)
- git.kernel.org/stable/c/405290be962b32eec842776fbe3bdf81f15b1676 (opens in a new tab)
- git.kernel.org/stable/c/8e48d8d51ab37b7decfbff3e2844e027a52ad6ea (opens in a new tab)