CVE-2026-46124: Linux kernel · isofs: validate block number from NFS file handle in isofs_export_iget
Affects Linux kernelSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.5 High · fixed in 5.15.0-1112.119~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% 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 +78
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 28 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-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 patch is available and should be applied to affected Linux kernel versions to properly validate block numbers in isofs NFS exports. The fix rejects block numbers greater than or equal to the total number of zones, preventing out-of-range reads. Systems exporting isofs over NFS from loop-mounted images should upgrade to a patched kernel version. No additional mitigations are indicated by the vendor advisory.
Description
A vulnerability in the Linux kernel's isofs NFS export code allows an attacker with authenticated NFS access to cause the server to read arbitrary in-range blocks from the backing device. This occurs because the block number from the NFS file handle is insufficiently validated before being passed to isofs_export_iget(), potentially exposing unrelated data as directory metadata. The issue affects systems exporting isofs over NFS from loop-mounted images. A patch is available that properly rejects out-of-range block numbers.
References
- ubuntu.com/security/CVE-2026-46124 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-46124 (opens in a new tab)
- git.kernel.org/linus/24376458138387fb251e782e624c7776e9826796 (opens in a new tab)
- git.kernel.org/stable/c/0a1af74ae2177bda3aee0837a0546309aa539d0d (opens in a new tab)
- git.kernel.org/stable/c/24376458138387fb251e782e624c7776e9826796 (opens in a new tab)
- git.kernel.org/stable/c/4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6 (opens in a new tab)
- git.kernel.org/stable/c/afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b (opens in a new tab)
- git.kernel.org/stable/c/bb0988ed4f2e26d59bbb58f644cb3a55b7521e21 (opens in a new tab)
- ubuntu.com/security/notices/USN-8566-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8568-1 (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-8593-1 (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)