CVE-2021-3563Network attack vector

Unauthorized project access via truncated application secrets

Published Aug 26, 2022 · Updated Feb 13, 2025

Application-secret verification in OpenStack Keystone 21.0.0 and earlier allows remote attackers to authenticate with a matching 72-byte prefix. The application-credential backend uses bcrypt verification, which silently ignores secret bytes after the algorithm's 72-byte input limit. An attacker who obtains or guesses the effective prefix receives the credential owner's delegated project access; application-credential authentication must be enabled.

CVSS severity7.4
High
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Application-secret verification in OpenStack Keystone 21.0.0 and earlier allows remote attackers to authenticate with a matching 72-byte prefix. The application-credential backend uses bcrypt verification, which silently ignores secret bytes after the algorithm's 72-byte input limit. An attacker who obtains or guesses the effective prefix receives the credential owner's delegated project access; application-credential authentication must be enabled.

The record

CVE
CVE-2021-3563
Published
Aug 26, 2022
Updated
Feb 13, 2025
Vendor
OpenStack
Product
Keystone
Classifications
CWE-863, T1110
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 26, 2022CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=Not-known

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenStack · Keystoneversion=Not-known

Published CVSS scores

9.1GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
7.4NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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