CVE-2026-28688
Description
A flaw was found in ImageMagick. Processing commands related to MSL writing, specifically cloning an image structure for output, can cause a heap use-after-free vulnerability and result in a denial of service.
Statement
To exploit this issue, an attacker needs to convince a user to process a specially crafted file that makes ImageMagick use the MSL encoder to write or output an image. The malicious file, usually an .msl script or an image designed to invoke MSL processing, will contain instructions to trigger the cloning process and the use-after-free issue, with no evidence it can cause arbitrary command execution. Due to these reasons, this flaw has been rated with a moderate severity.
Mitigation
To mitigate this vulnerability, disable the vulnerable encoder by adding the following line to the ImageMagick policy.xml file, typically located in the directory /etc/ImageMagick-7/, /etc/ImageMagick-6/ or /etc/ImageMagick/:
<policy domain="coder" rights="none" pattern="MSL" />
To reduce the risk of exploitation, avoid processing untrusted MSL files with ImageMagick. If ImageMagick is deployed in a way that it processes files from untrusted sources automatically, consider running the application inside a container or a restricted sandbox environment to limit the potential security impact.
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 | 5.5 | 5.3 | N/A |
| Attack Vector | Local | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | Low | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
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