Ollama up to 0.13.5 /api/chat mtmd_helper_bitmap_init_from_buf null pointer dereference

Summaryinfo

A vulnerability identified as critical has been detected in Ollama up to 0.13.5. Affected by this issue is the function mtmd_helper_bitmap_init_from_buf of the file /api/chat. The manipulation leads to null pointer dereference. This vulnerability is uniquely identified as CVE-2025-15514. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Ollama up to 0.13.5. This issue affects the function mtmd_helper_bitmap_init_from_buf of the file /api/chat. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-395. Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer. Impacted is availability. The summary by CVE is:

Ollama 0.11.5-rc0 through current version 0.13.5 contain a null pointer dereference vulnerability in the multi-modal model image processing functionality. When processing base64-encoded image data via the /api/chat endpoint, the application fails to validate that the decoded data represents valid media before passing it to the mtmd_helper_bitmap_init_from_buf function. This function can return NULL for malformed input, but the code does not check this return value before dereferencing the pointer in subsequent operations. A remote attacker can exploit this by sending specially crafted base64 image data that decodes to invalid media, causing a segmentation fault and crashing the runner process. This results in a denial of service condition where the model becomes unavailable to all users until the service is restarted.

The weakness was disclosed by bob14 and weblover. The advisory is shared at huntr.com. The identification of this vulnerability is CVE-2025-15514 since 01/12/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-2400). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Ollama

Version

• 0.13.0
• 0.13.1
• 0.13.2
• 0.13.3
• 0.13.4
• 0.13.5

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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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