CVE-2025-57803
Description
A flaw was found in ImageMagick. In 32-bit builds, the Bitmap encoder miscalculates the stride value when processing images with very large with. Mathematically, the stride value is calculated as width multiplied by 3 but the theoretical limit of such value is 2^32 for 32-bit integers. So, if this value is exceeded, the encoder uses modulo to convert it down and then takes the smaller value as the actual stride length. This is problematic because the pixel data starts to overlap when being added to the buffer due to the small stride value messing up the rows. This heap buffer overflow allows an attacker to cause a denial of service or, with crafted input, potentially execute arbitrary code.
Statement
This vulnerability is specific to 32-bit ImageMagick builds. Red Hat predominantly only ships 64-bit builds of Kea on its platforms and so the vulnerability affects only customers that install i686 arch rpm packages as these are the only 32-bit builds Red Hat provides. The flaw occurs in the WriteBMPImage function when computing bytes_per_line for 24-bpp BMP images. An integer overflow causes the stride to underflow to a small value, while the writer still emits 3 × width bytes per row. The mismatch immediately produces a large, attacker-controlled heap overwrite.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 8.8 | 7.5 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | High |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
The Attack complexity is high and not low because the the affected Red Hat products require users to install the packages locally to run them and coordinating a remote attack on a local user's CLI is technical and requires a lot of know-how. Plus, some level of privilege has to be obtained in order to execute such attack remotely which is why PR: L.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the overflow/wraparound results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows, which can be used to execute arbitrary code. This is usually outside the scope of the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
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