What is CVE-2023-27580?

CVE-2023-27580 is a high-severity vulnerability in Codeigniter Shield, classified under Use of Password Hash With Insufficient Computational Effort. CVSS score: 7.5/10. Published 2023-03-13.

How severe is CVE-2023-27580?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Codeigniter Shield

CVE-2023-27580

CodeIgniter Shield provides authentication and authorization for the CodeIgniter 4 PHP framework. An improper implementation was found in the password storage process. All hashed passwords stored in Shield v1.0.0-beta.3 or earlier are easier to crack than expected due to the vulnerability. Therefore, they should be removed as soon as possible. If an attacker gets (1) the user's hashed password by Shield, and (2) the hashed password (SHA-384 hash without salt) from somewhere, the attacker may easily crack the user's password. Upgrade to Shield v1.0.0-beta.4 or later to fix this issue. After upgrading, all users’ hashed passwords should be updated (saved to the database). There are no known workarounds.

Published 2023-03-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (41.6th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Codeigniter Shield — versions 1.0.0
Codeigniter4 Shield — versions < 1.0.0-beta.4

Weakness classification (CWE)

CWE-916 — Use of Password Hash With Insufficient Computational Effort

References

github.com/codeigniter4/shield/security/advisories/GHSA-c5vj-f36q-p9vg (Vendor Advisory)
github.com/codeigniter4/shield/commit/ea9688dd01d100193d834117dbfc2cfabcf9ea0b (Patch)
blog.ircmaxell.com/2015/03/security-issue-combining-bcrypt-with.html (Third Party Advisory)
cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html (Not Applicable)
github.com/codeigniter4/shield/blob/develop/UPGRADING.md (Vendor Advisory)
www.scottbrady91.com/authentication/beware-of-password-shucking (Third Party Advisory)

Frequently asked questions

What is CVE-2023-27580?: CVE-2023-27580 is a high-severity vulnerability in Codeigniter Shield, classified under Use of Password Hash With Insufficient Computational Effort. CVSS score: 7.5/10. Published 2023-03-13.
How severe is CVE-2023-27580?: High severity. CVSS v3 base score is 7.5 out of 10.