CVE-2026-98215: linux

CVSS: UnknownReceived
AliasesUBUNTU-CVE-2026-98215DEBIAN-CVE-2026-98215
Published 06-10-2026Last modified 19-10-2026
Open JSON

Vulnerability summary

CVE-2026-98215 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.4% of scored vulnerabilities.

Overall risk
0/100
0100
Minimal · default modelHow is this calculated?
CVSS score
Not scored
010
No CVSS score recorded
EPSS score
0.21%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:12131-1

Timeline

  1. 06-10-2026
    PublishedVulnerability first disclosed.
  2. 19-10-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

Risk metrics not yet published.

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

10%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

06-10-202621-10-2026
EPSS score
0.21%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu119 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian1 product
  • linuxAll versions (No fix recorded) | < 6.12.113-1 | < 7.2.8-1
Linux1 product
  • linux≥ bc6c380c1159de52a252ed11f19a42c47f60a735, < caa1b913d90d5dc07073733326d2af0f0288f089 | ≥ 8bacd09f12c27710228562e4d13163e58c5f4a45, < 6aaeec59aadcd1eafc18b049f1b759fb6b9d9569 | ≥ d844702198395d3f80222777030f69db6be6b709, < 9d99b770e7b67b00bdef9005b928aad13e1d679b | ≥ 82544d36b1729153c8aeb179e84750f0c085d3b1, < ff20d16b2e8230c034e21540043df47222dcc09b | ≥ 82544d36b1729153c8aeb179e84750f0c085d3b1, < 8c0c602202b9a4909b00bc3354e3c0355bc69e65 | cd0e707a927a70cdfd8bc5a512a9719a87f5ed51 | ≥ 6.6.144, < 6.6.158 | ≥ 6.12.95, < 6.12.112 | ≥ 6.18.38, < 6.18.54 | ≥ 7.0.4, < 7.1 | 7.1

3 vendors · 121 products

References

9 links