CVE-2026-56374
Description
A heap buffer overflow vulnerability exists in ImageMagick and Magick.NET's FTXT encoder due to missing boundary checks for the ftxt:format parameter. A remote attacker could exploit this using a specially crafted FTXT image to cause a denial of service or disclose sensitive information.
Statement
This low-impact heap buffer overflow in ImageMagick's FTXT encoder, caused by insufficient boundary checks, could lead to denial of service or information disclosure if a user opens a specially crafted FTXT file.
Mitigation
To mitigate this, disable the vulnerable FTXT format by adding the following line to your ImageMagick security policy file (typically /etc/ImageMagick-7/policy.xml):
<policy domain="coder" rights="none" pattern="FTXT" />
Applying this mitigation will immediately block ImageMagick from processing any files in the FTXT format, but requires no service restarts or downtime.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.3 | 7.1 | 3.3 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | Required | Required | Required |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | High | None |
| Integrity Impact | None | None | None |
| Availability Impact | Low | High | Low |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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