CVE-2016-4911: The Fernet Token Provider in OpenStack Identity (Keystone) 9.0.x before 9.0.1 (mitaka) allows remote authentic

Routine

MEDIUM 4.3DOWNGRADE

CVE-2016-4911 is a medium-severity flaw (CVSS 4.3) affecting openstack identity. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Fernet Token Provider in OpenStack Identity (Keystone) 9.0.x before 9.0.1 (mitaka) allows remote authenticated users to prevent revocation of a chain of tokens and bypass intended access restrictions by rescoping a token.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.4% (top 27%)
CISA exploited list	No
Weakness	CWE-284
Published	2016-06-13
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: keystone

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2016-06-13 14:59 UTCPublished CVE record published
2026-06-17 00:48 UTCUpdated Record last modified

keystone openstack identity DOWNGRADE

Affected: 9.0.0.0 rc1 · 9.0.0.0 rc2 · 9.0.0.0 rc3

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0.0.0

1. Check installed version

apt-cache policy openstack-identity || rpm -q openstack-identity || openstack-identity --version

2. No fixed release: DOWNGRADE to a release before 9.0.0.0 (Debian / Ubuntu)

apt-cache madison openstack-identity sudo apt install openstack-identity=<VERSION_BEFORE_9.0.0.0> sudo apt-mark hold openstack-identity

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openstack-identity sudo dnf downgrade openstack-identity-<VERSION_BEFORE_9.0.0.0> sudo dnf versionlock add openstack-identity

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2016-4911?

openstack identity: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2016-4911 being exploited?

CVE-2016-4911 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2016-4911 affect?

CVE-2016-4911 affects openstack identity. Severity is medium (CVSS 4.3). The Fernet Token Provider in OpenStack Identity (Keystone) 9.0.x before 9.0.1 (mitaka) allows remote authenticated users to prevent revocation of a chain of tokens and bypass intended access restrictions by rescoping a token.

How urgent is CVE-2016-4911?

Priority 33/100. No elevated risk signals yet.

Software pages

OpenStack vulnerabilities

References

← Back to latest CVEs