CVE-2026-46101: Linux kernel · netfilter: reject zero shift in nft_bitwise
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1112.119~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1112.119~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2 +72
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 May 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 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-ibmpkg:deb/ubuntu/linux-ibm?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 and has been incorporated into Linux kernel updates. Users should apply the official Linux kernel security updates that reject zero shift operands in nft_bitwise expressions during initialization. The vendor advisory from Ubuntu confirms that this issue is addressed in their security notices. Systems running affected kernel versions should be updated to versions including this fix to mitigate the vulnerability.
Description
A vulnerability in the Linux kernel's netfilter nft_bitwise component allowed zero shift operands in left and right shift expressions during initialization, causing undefined behavior. This flaw was addressed by rejecting zero shift operands in the control plane to prevent malformed rules from reaching the packet path. The issue affects multiple Linux kernel versions prior to 5.15.0-186.196 and specific listed versions. The vulnerability has a medium severity with a CVSS score of 5.5 and does not impact confidentiality or integrity but can cause availability issues.
References
- ubuntu.com/security/CVE-2026-46101 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-46101 (opens in a new tab)
- git.kernel.org/linus/fe11e5c40817b84abaa5d83bfb6586d8412bfd07 (opens in a new tab)
- ubuntu.com/security/notices/USN-8488-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8489-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8488-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8507-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8569-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8597-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-46101 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- git.kernel.org/stable/c/4fccea585631621c975883911a08d15b6671f7dc (opens in a new tab)
- git.kernel.org/stable/c/6f820139d16a4c9865a145d4a9cf9c92cc632c14 (opens in a new tab)
- git.kernel.org/stable/c/9ad26c272405f53834871cc2e46b9b5393a666c3 (opens in a new tab)
- git.kernel.org/stable/c/9baa08d6b6b096fad70049533f0d705d85fdc979 (opens in a new tab)
- git.kernel.org/stable/c/bffef0acec9c3b837a785248a893137fb7f26c95 (opens in a new tab)
- git.kernel.org/stable/c/ca24f1243ad1a4d12d6a23876bbbe3ed02099853 (opens in a new tab)
- git.kernel.org/stable/c/f370205974f171a5868c13ff30d7642fed46e47b (opens in a new tab)
- git.kernel.org/stable/c/fe11e5c40817b84abaa5d83bfb6586d8412bfd07 (opens in a new tab)