TCPDF has incorrect comparison
An issue was discovered in TCPDF before 6.8.0. unserializeTCPDFtag uses != (aka loose comparison) and does not use a constant-time function to compare TCPDF tag hashes.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | tecnickcom/tcpdf | < 6.8.0 | 6.8.0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2024-56522
- https://github.com/tecnickcom/TCPDF/commit/d54b97cec33f4f1a5ad81119a82085cad93cec89
- https://github.com/tecnickcom/TCPDF
- https://github.com/tecnickcom/TCPDF/compare/6.7.8...6.8.0
- https://lists.debian.org/debian-lts-announce/2025/06/msg00004.html
- https://tcpdf.org
- https://www.php.net/manual/en/types.comparisons.php
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-697, CWE-843- Platform
- Composer
- Package
tecnickcom/tcpdf- Disclosed
- 27.12.2024
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-w95c-7994-ghpr - CC BY 4.0
Vulnerability history: tecnickcom/tcpdf
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 8
- First → latest
- 10.2022 12.2024
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 2
- Medium 5
Disclosures per year
- 2022: 1
- 2023: 0
- 2024: 7
- 2025: 0
- 2026: 0
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TCPDF has incorrect comparison this entry
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