Skip to main content

Linux EUVDEUVD-2026-93143

| CVE-2026-98215
2026-10-06 Linux GHSA-4rhv-8vqv-p9w9
View
Monitor Track and reassess. Why: No CVSS yet + weak signal (CWE or non-zero EPSS).
Patch available 0.2% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisCVE.org

In the Linux kernel, the following vulnerability has been resolved:

selinux: preserve user SID across nested backing files

SELinux saves the user file SID in a backing-file security blob so it remains available after mmap() replaces vma->vm_file with a backing file.

For nested backing files (overlayfs over overlayfs, or FUSE passthrough backed by overlayfs), user_file may itself be a backing file. Its fsec->sid is the SID of the mounter that opened it, rather than the user that opened the top-level file. mprotect() then checks fd { use } against the mounter SID. This can incorrectly deny access without a domain transition, or check the wrong target SID after one.

Copy the saved user SID when user_file is a backing file. Keep using the regular file SID for the first backing layer.

With two nested overlayfs mounts and SELinux enforcing, mprotect(PROT_READ) returns EACCES with an fd { use } denial against the mounter SID. With this change, mprotect() succeeds.

Tested on arm64 QEMU with a small BusyBox initramfs and a purpose-built SELinux policy. The original test was also repeated with Fedora Cloud Base 44 userspace and gave the same result.

Affected VersionsENISA

Linux 82544d36b1729153c8aeb179e84750f0c085d3b1 <8c0c602202b9a4909b00bc3354e3c0355bc69e65
Linux 82544d36b1729153c8aeb179e84750f0c085d3b1 <ff20d16b2e8230c034e21540043df47222dcc09b
Linux 6.12.95 <6.12.112
Linux d844702198395d3f80222777030f69db6be6b709 <9d99b770e7b67b00bdef9005b928aad13e1d679b
Linux patch: 7.3-rc4
Linux 6.6.144 <6.6.158
Linux bc6c380c1159de52a252ed11f19a42c47f60a735 <caa1b913d90d5dc07073733326d2af0f0288f089
Linux 6.18.38 <6.18.54
Linux patch: 7.2.8
Linux 8bacd09f12c27710228562e4d13163e58c5f4a45 <6aaeec59aadcd1eafc18b049f1b759fb6b9d9569
Linux 7.1
Linux 7.0.4 <7.1
Linux patch: 6.18.54
Linux patch: 0
Linux patch: 6.6.158
Linux cd0e707a927a70cdfd8bc5a512a9719a87f5ed51
Linux patch: 6.12.112

Affected Packages

euvd linux fix: 6.6.158, 6.12.112, 6.18.54, 7.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Know when the next one hits your stack

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Lifecycle Timeline

2
Patch available
Oct 06, 2026 - 10:02 EUVD
CVE Published
Oct 06, 2026 - 08:44 cve.org
UNKNOWN (no severity yet)

Threat Intelligence Overview

EPSS Score
0.2%
Top 90% exploitable
Threat Intel
1
1 sources
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity Not scored yet
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
No CVSS yet + weak signal (CWE or non-zero EPSS)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy