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CVE-2016-4911

18
FAUCET Score

CVE-2016-4911 describes a vulnerability in the Fernet Token Provider of OpenStack Identity (Keystone) versions 9.0.x prior to 9.0.1 (Mitaka). This flaw allows remote authenticated users to prevent the revocation of token chains and bypass access restrictions by rescoping a token. The vulnerability has a CVSS v3.1 score of 4.3 (Medium), indicating a low attack complexity and impact limited to integrity, with no confidentiality or availability impact. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
9.0.0.0CPE matchmatch criteria
cpe:2.3:a:keystone:openstack_identity:9.0.0.0:rc1:*:*:*:*:*:*
9.0.0.0CPE matchmatch criteria
cpe:2.3:a:keystone:openstack_identity:9.0.0.0:rc2:*:*:*:*:*:*
9.0.0.0CPE matchmatch criteria
cpe:2.3:a:keystone:openstack_identity:9.0.0.0:rc3:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.3MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.40%
Probability of exploitation in next 30 days
EPSS Percentile
69.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-23
Model: v2026.06.15
This CVE's current EPSS score of 0.0140 is in the 83rd percentile among its peer group of 21,939 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

pippatch availablevia ghsa
Product: keystoneFixed in: 9.0.1

Vendor Advisories (2)

pipGHSA-f82m-w3p3-cgp3medium

OpenStack Identity Keystone Improper Access Control

May 17, 2022
redhatCVE-2016-4911Moderate

openstack-keystone: Incorrect Audit IDs in Keystone Fernet Tokens can result in revocation bypass

May 17, 2016

References

bugs.launchpad.net / keystone/+bug/1577558
Vendor Advisory
review.openstack.org
Vendor Advisory
security.openstack.org / ossa/OSSA-2016-008.html
PatchVendor Advisory
openwall.com / lists/oss-security/2016/05/17/10
Mailing List
openwall.com / lists/oss-security/2016/05/17/11
Mailing List
securityfocus.com / bid/90728
Third Party AdvisoryVDB Entry