CVE-2023-0567Public exploit

Authentication bypass via dollar-truncated BCrypt salt

Published Feb 16, 2023 · Updated Jul 19, 2026

Improper BCrypt hash validation in PHP 8.0 before 8.0.28, 8.1 before 8.1.16, and 8.2 before 8.2.3 allows attackers to bypass authentication. The crypt_blowfish salt parser accepts an embedded dollar sign as an early terminator, then fixed-size copying and length handling return the malformed setting unchanged for a successful comparison. An invalid BCrypt hash must reach the application's password store; password_verify() then accepts any password for that entry.

CVSS severity7.7
High
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper BCrypt hash validation in PHP 8.0 before 8.0.28, 8.1 before 8.1.16, and 8.2 before 8.2.3 allows attackers to bypass authentication. The crypt_blowfish salt parser accepts an embedded dollar sign as an early terminator, then fixed-size copying and length handling return the malformed setting unchanged for a successful comparison. An invalid BCrypt hash must reach the application's password store; password_verify() then accepts any password for that entry.

The record

CVE
CVE-2023-0567
Published
Feb 16, 2023
Updated
Jul 19, 2026
Vendor
The PHP Group
Product
PHP
Classifications
CWE-916, T1190
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 16, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.0.* <8.0.28
  2. Affected versionversion=8.1.* <8.1.16
  3. Affected versionversion=8.2.* <8.2.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The PHP Group · PHPversion=8.0.* <8.0.28; version=8.1.* <8.1.16; version=8.2.* <8.2.3

Published CVSS scores

7.7The PHP GroupCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
8.1CISACVSS:3.1/AV:A/AC:L/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

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-916Use of Password Hash With Insufficient Computational Effort
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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