It was discovered in the Linux kernel before 4.11-rc8 that root can gain direct access to an internal keyring, such as '.dns_resolver' in R…

published 2018-07-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2016-10408

cvss: 4.4; version 3.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

It was discovered in the Linux kernel before 4.11-rc8 that root can gain direct access to an internal keyring, such as '.dns_resolver' in RHEL-7 or '.builtin_trusted_keys' upstream, by joining it as its session keyring. This allows root to bypass module signature verification by adding a new public key of its own devising to the keyring.

Patch / fix

distros 4 links 1

debian ubuntu red hat suse

linux Debian 14, Debian 13, Debian 12 4.9.25-1

debian advisories DEBIAN-CVE-2016-9604

linux Ubuntu 14.04 LTS 3.13.0-132.181
linux Ubuntu 16.04 LTS 4.4.0-79.100
linux-aws Ubuntu 16.04 LTS 4.4.0-1018.27
linux-gke Ubuntu 16.04 LTS 4.4.0-1014.14
linux-hwe Ubuntu 16.04 LTS 4.10.0-32.36~16.04.1
linux-raspi2 Ubuntu 16.04 LTS 4.4.0-1057.64
linux-lts-xenial Ubuntu 14.04 LTS 4.4.0-79.100~14.04.1
linux-snapdragon Ubuntu 16.04 LTS 4.4.0-1059.63

ubuntu advisories UBUNTU-CVE-2016-9604

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-rt enterprise mrg 2 1:3.10.0-693.2.1.rt56.585.el6rt
kernel-rt-trace enterprise mrg 2 1:3.10.0-693.2.1.rt56.585.el6rt
kernel-rt-vanilla enterprise mrg 2 1:3.10.0-693.2.1.rt56.585.el6rt
kernel-rt-firmware enterprise mrg 2 1:3.10.0-693.2.1.rt56.585.el6rt
kernel-rt-debuginfo-common-x86_64 enterprise mrg 2 1:3.10.0-693.2.1.rt56.585.el6rt
kernel-rt RHEL 7 EXTRAS_RT 3.10.0-693.rt56.617.el7
kernel-rt-kvm RHEL 7 EXTRAS_RT 3.10.0-693.rt56.617.el7
kernel-rt-trace RHEL 7 EXTRAS_RT 3.10.0-693.rt56.617.el7

red hat advisories RHSA-2017:2669 RHSA-2017:2077 RHSA-2017:1842

kernel-ec2 SLE Module for Public Cloud 12 3.12.61-52.101.1
kernel-ec2 SLE Module for Public Cloud 12 3.12.74-60.64.40.1
kernel-xen SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 3.12.74-60.64.40.1
kernel-syms SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 3.12.74-60.64.40.1
kernel-source SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 3.12.74-60.64.40.1
kernel-default SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 3.12.74-60.64.40.1
kernel-obs-build SLE Software Development Kit 12 SP1 3.12.74-60.64.40.1
kernel-xen SLES 12-LTSS 3.12.61-52.101.1

suse advisories SUSE-SU-2017:2920-1 SUSE-SU-2017:1360-1

git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ee8… commit

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-2016-9604 updated 2026-11-07 cvss 4.4

kernel: security: The built-in keyrings for security tokens can be joined as a session and then modified by the root user

Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
affected: no fix available
Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-693.el7, kernel 3.10.0-693.el7, python-perf 3.10.0-693.el7, kernel-tools 3.10.0-693.el7, kernel-tools-libs 3.10.0-693.el7, kernel-abi-whitelists 3.10.0-693.el7, +1 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-693.el7 Red Hat Enterprise Linux ComputeNode (v. 7) perf 3.10.0-693.el7, kernel 3.10.0-693.el7, python-perf 3.10.0-693.el7, kernel-tools 3.10.0-693.el7, kernel-tools-libs 3.10.0-693.el7, kernel-abi-whitelists 3.10.0-693.el7, +1 more Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-693.el7
fixed: vendor fix RHSA-2017:1842
Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt 3.10.0-693.rt56.617.el7, kernel-rt-trace 3.10.0-693.rt56.617.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-693.rt56.617.el7 Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-693.rt56.617.el7, kernel-rt-kvm 3.10.0-693.rt56.617.el7, kernel-rt-trace 3.10.0-693.rt56.617.el7, kernel-rt-debug-kvm 3.10.0-693.rt56.617.el7, kernel-rt-trace-kvm 3.10.0-693.rt56.617.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-693.rt56.617.el7
fixed: vendor fix RHSA-2017:2077
Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-693.el7, kernel 3.10.0-693.el7, python-perf 3.10.0-693.el7, kernel-kdump 3.10.0-693.el7, kernel-tools 3.10.0-693.el7, kernel-tools-libs 3.10.0-693.el7, +6 more Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-693.el7, kernel-debuginfo-common-x86_64 3.10.0-693.el7, kernel-debuginfo-common-ppc64le 3.10.0-693.el7 Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-693.el7, kernel 3.10.0-693.el7, python-perf 3.10.0-693.el7, kernel-tools 3.10.0-693.el7, kernel-tools-libs 3.10.0-693.el7, kernel-abi-whitelists 3.10.0-693.el7, +1 more Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-693.el7
fixed: vendor fix RHSA-2017:1842
Red Hat MRG Realtime for RHEL 6 Server v.2 kernel-rt 3.10.0-693.2.1.rt56.585.el6rt, kernel-rt-trace 3.10.0-693.2.1.rt56.585.el6rt, kernel-rt-vanilla 3.10.0-693.2.1.rt56.585.el6rt, kernel-rt-firmware 3.10.0-693.2.1.rt56.585.el6rt, kernel-rt-debuginfo-common-x86_64 3.10.0-693.2.1.rt56.585.el6rt
fixed: vendor fix RHSA-2017:2669
Red Hat Enterprise Linux 5 kernel Red Hat Enterprise Linux Client (v. 7) kernel-headers 3.10.0-693.el7 Red Hat Enterprise Linux ComputeNode (v. 7) kernel-headers 3.10.0-693.el7 Red Hat Enterprise Linux Server (v. 7) kernel-headers 3.10.0-693.el7 Red Hat Enterprise Linux Workstation (v. 7) kernel-headers 3.10.0-693.el7
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

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.0	4.4	CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
NVD	3.0	4.4	CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
NVD	2.0	2.1	AV:L/AC:L/Au:N/C:N/I:P/A:N

Affected products

kernel security

Classification

Weakness

CWE-732 Incorrect Permission Assignment for Critical Resource
CWE-347 Improper Verification of Cryptographic Signature

Technology feeds

Linux kernel rss critical rss

References

git.kernel.org /pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ee8f844e3c5a73b999edf733df1c529d6503ec2f
patch, vendor-advisory
access.redhat.com /errata/RHSA-2017:2669
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:2077
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:1842
vendor-advisory, third-party-advisory
bugzilla.redhat.com /show_bug.cgi?id=CVE-2016-9604
issue-tracking, third-party-advisory
bugzilla.novell.com /show_bug.cgi?id=1035576
issue-tracking, third-party-advisory
people.canonical.com /~ubuntu-security/cve/2016/CVE-2016-9604.html
third-party-advisory
securityfocus.com /bid/102135
vdb-entry, third-party-advisory

Sources

CVE List CVE-2016-9604
NVD CVE-2016-9604

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.

Summary