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Fencer Vulns
medium 5.5

CVE-2019-9213 json

In the Linux kernel before 4.20.14, expand_downwards in mm/mmap.c lacks a check for the mmap minimum address, which makes it easier for att…

published 2019-03-05 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-18588

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
5.7%
EPSS 5.7% chance of exploitation in 30 days, percentile 93%
public exploits
3
Metasploit, Exploit-DB

Summary

In the Linux kernel before 4.20.14, expand_downwards in mm/mmap.c lacks a check for the mmap minimum address, which makes it easier for attackers to exploit kernel NULL pointer dereferences on non-SMAP platforms. This is related to a capability check for the wrong task.

Patch / fix

  • linux linux_kernel 4.9.162, 4.14.105, 4.19.27, 4.20.14
  • linux Debian 14, Debian 13, Debian 12 4.19.28-1

debian advisories DEBIAN-CVE-2019-9213

  • linux Ubuntu 14.04 LTS 3.13.0-168.218
  • linux Ubuntu 16.04 LTS 4.4.0-145.171
  • linux Ubuntu 18.04 LTS 4.15.0-47.50
  • linux-aws Ubuntu 14.04 LTS 4.4.0-1040.43
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1079.89
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1035.37
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1029.31~16.04.1
  • linux-gcp Ubuntu 18.04 LTS 4.15.0-1029.31

ubuntu advisories UBUNTU-CVE-2019-9213

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-alt RHEL 7 4.14.0-115.7.1.el7a
  • perf RHEL 7 4.14.0-115.7.1.el7a
  • kernel RHEL 7 4.14.0-115.7.1.el7a
  • python-perf RHEL 7 4.14.0-115.7.1.el7a
  • kernel-tools RHEL 7 4.14.0-115.7.1.el7a
  • kernel-tools-libs RHEL 7 4.14.0-115.7.1.el7a
  • kernel-bootwrapper RHEL 7 4.14.0-115.7.1.el7a
  • kernel-abi-whitelists RHEL 7 4.14.0-115.7.1.el7a

red hat advisories RHSA-2019:0831RHSA-2019:1480RHSA-2019:1479

  • kernel-ec2 SLE Module for Public Cloud 12 3.12.74-60.64.110.1
  • kernel-azure SLES for SAP 12 SP3, SLES 12 SP3 4.4.176-4.25.1
  • kernel-syms-azure SLES for SAP 12 SP3, SLES 12 SP3 4.4.176-4.25.1
  • kernel-source-azure SLES for SAP 12 SP3, SLES 12 SP3 4.4.176-4.25.1
  • kernel-syms SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +2 more 4.4.121-92.104.1
  • kernel-source SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +2 more 4.4.121-92.104.1
  • kernel-default SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +3 more 4.4.121-92.104.1
  • kgraft-patch-SLE12-SP2_Update_28 SLES for SAP 12 SP2, SLES 12 SP2-LTSS, OpenStack Cloud 7 +1 more 1-3.3.1

suse advisories SUSE-SU-2019:1289-1SUSE-SU-2019:14051-1SUSE-SU-2019:0901-1SUSE-SU-2019:0845-1SUSE-SU-2019:0828-1SUSE-SU-2019:0801-1

  • kernel-syms openSUSE Leap 15.0 4.12.14-lp150.12.58.1
  • kernel-obs-qa openSUSE Leap 15.0 4.12.14-lp150.12.58.1
  • kernel-source openSUSE Leap 15.0 4.12.14-lp150.12.58.1
  • kernel-default openSUSE Leap 15.0 4.12.14-lp150.12.58.1
  • kernel-vanilla openSUSE Leap 15.0 4.12.14-lp150.12.58.1
  • kernel-kvmsmall openSUSE Leap 15.0 4.12.14-lp150.12.58.1
  • kernel-obs-build openSUSE Leap 15.0 4.12.14-lp150.12.58.1

opensuse advisories openSUSE-SU-2019:1193-1

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-2019-9213 updated cvss 5.5

kernel: lack of check for mmap minimum address in expand_downwards in mm/mmap.c leads to NULL pointer dereferences exploit on non-SMAP platforms

  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-80.4.2.el8_0, kernel-debuginfo-common-aarch64 4.18.0-80.4.2.el8_0, kernel-debuginfo-common-ppc64le 4.18.0-80.4.2.el8_0 Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-80.4.2.el8_0, kernel 4.18.0-80.4.2.el8_0, bpftool 4.18.0-80.4.2.el8_0, kernel-core 4.18.0-80.4.2.el8_0, kernel-tools 4.18.0-80.4.2.el8_0, python3-perf 4.18.0-80.4.2.el8_0, +15 more
    fixed: vendor fix “Enabling selinux prevents the public exploit from working correctly.” RHSA-2019:1479
  • Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) perf 4.14.0-115.7.1.el7a, kernel 4.14.0-115.7.1.el7a, kernel-alt 4.14.0-115.7.1.el7a, python-perf 4.14.0-115.7.1.el7a, kernel-tools 4.14.0-115.7.1.el7a, kernel-tools-libs 4.14.0-115.7.1.el7a, +3 more Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) kernel-debuginfo-common-ppc64le 4.14.0-115.7.1.el7a
    fixed: vendor fix “Enabling selinux prevents the public exploit from working correctly.” RHSA-2019:0831
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-core 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-modules 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-debug-core 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-debug-modules 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-modules-extra 4.18.0-80.4.2.rt9.152.el8_0, +2 more Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-kvm 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-core 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-modules 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-debug-kvm 4.18.0-80.4.2.rt9.152.el8_0, kernel-rt-debug-core 4.18.0-80.4.2.rt9.152.el8_0, +4 more
    fixed: vendor fix “Enabling selinux prevents the public exploit from working correctly.” RHSA-2019:1480
  • 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, python-perf, kernel-kdump, +8 more Red Hat Enterprise MRG 2 kernel
    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

Timeline

  1. First public exploit (Metasploit exploit/linux/local/rds_atomic_free_op_null_pointer_deref_priv_esc)
  2. Published

Exploit prediction

5.67% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Metasploit exploit/linux/local/rds_atomic_free_op_null_pointer_deref_priv_esc Reliable Datagram Sockets (RDS) rds_atomic_free_op NULL pointer dereference Privilege Escalation metasploit exploit, good rank, 2018-11-01
  • EDB-47957 Reliable Datagram Sockets (RDS) - rds_atomic_free_op NULL pointer dereference Privilege Escalation (Metasploit) local, 2020-01-23
  • EDB-46502 Linux < 4.20.14 - Virtual Address 0 is Mappable via Privileged write() to /proc/*/mem dos, 2019-03-06
  • bugs.chromium.org https://bugs.chromium.org/p/project-zero/issues/detail?id=1792 referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/156053/Reliable-Datagram-Sockets-RDS-rds_atomic_free_op-Privilege-Escalation.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns 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.