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Fencer Intel
medium 5.5

CVE-2018-1093 json

The ext4_valid_block_bitmap function in fs/ext4/balloc.c in the Linux kernel through 4.15.15 allows attackers to cause a denial of service…

published 2018-04-02 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-11743

cvss
5.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

The ext4_valid_block_bitmap function in fs/ext4/balloc.c in the Linux kernel through 4.15.15 allows attackers to cause a denial of service (out-of-bounds read and system crash) via a crafted ext4 image because balloc.c and ialloc.c do not validate bitmap block numbers.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 4.15.17-1

debian advisories DEBIAN-CVE-2018-1093

  • linux Ubuntu 14.04 LTS 3.13.0-157.207
  • linux Ubuntu 16.04 LTS 4.4.0-128.154
  • linux Ubuntu 18.04 LTS 4.15.0-33.36
  • linux-aws Ubuntu 14.04 LTS 4.4.0-1023.23
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1061.70
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1020.20
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1018.19~16.04.2
  • linux-gcp Ubuntu 18.04 LTS 4.15.0-1018.19

ubuntu advisories UBUNTU-CVE-2018-1093

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-syms SLES 12 SP2-BCL, OpenStack Cloud 7, Enterprise Storage 4 +2 more 4.4.121-92.85.1
  • kernel-source SLES 12 SP2-BCL, OpenStack Cloud 7, Enterprise Storage 4 +2 more 4.4.121-92.85.1
  • kernel-default SLES 12 SP2-BCL, OpenStack Cloud 7, Enterprise Storage 4 +2 more 4.4.121-92.85.1
  • kgraft-patch-SLE12-SP2_Update_23 SLES 12 SP2-BCL, OpenStack Cloud 7, Enterprise Storage 4 +2 more 1-3.5.1
  • kernel-syms SLE Module for Development Tools 15 4.12.14-25.3.1
  • kernel-source SLE Module for Development Tools 15, SLE Module for Basesystem 15 4.12.14-25.3.1
  • kernel-default SLE Workstation Extension 15, SLE Module for Legacy 15, SLE Module for Basesystem 15 +2 more 4.12.14-25.3.1
  • kernel-vanilla SLE Module for Development Tools 15 4.12.14-25.3.1

suse advisories SUSE-SU-2018:1855-2SUSE-SU-2018:2092-1SUSE-SU-2018:1855-1SUSE-SU-2018:1816-1SUSE-SU-2018:1762-1SUSE-SU-2018:1761-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-1093 updated cvss 4.6

kernel: Out of bounds read in ext4/balloc.c:ext4_valid_block_bitmap() causes crash with crafted ext4 image

  • Red Hat Enterprise Linux 5 kernel Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, kernel-alt, python-perf, +9 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-core, kernel-tools, python3-perf, +17 more Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.92% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 5.5 CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 7.1 AV:N/AC:M/Au:N/C:N/I:N/A:C

Affected products

  • n/a Linux kernel through version 4.15

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.