CVE-2026-20889
Heap-Based Buffer Overflow in LibRaw x3f_thumb_loader Component
Publication date: 2026-04-07
Last updated on: 2026-04-10
Assigner: Talos
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| libraw | libraw | 0.22.0 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-190 | The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-20889 is a critical heap-based buffer overflow vulnerability in the x3f_thumb_loader function of the LibRaw library, which processes RAW image files from cameras. The flaw occurs because the function calculates the size of a thumbnail buffer using 32-bit arithmetic, which can overflow if the product of image dimensions is too large. This causes the program to allocate a smaller buffer than needed.
When the program copies thumbnail data into this undersized buffer, it writes beyond the allocated memory, leading to heap corruption. An attacker can exploit this by providing a specially crafted malicious X3F file that triggers this overflow.
This vulnerability can potentially allow arbitrary code execution due to the heap corruption caused by the overflow.
How can this vulnerability impact me? :
If you use an application that processes untrusted Sigma/Foveon X3F RAW image files with the vulnerable LibRaw library compiled with X3F support enabled, an attacker can exploit this vulnerability by supplying a malicious file.
- Heap buffer overflow leading to heap corruption.
- Potential arbitrary code execution, allowing an attacker to run malicious code on your system.
- Possible application crashes or denial of service due to memory corruption.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability occurs when processing specially crafted Sigma/Foveon X3F RAW image files using the LibRaw library with the x3f_thumb_loader functionality enabled. Detection involves identifying if your system or applications use a vulnerable version of LibRaw compiled with -DUSE_X3FTOOLS and if they process untrusted X3F files.
To detect potential exploitation attempts or presence of malicious files, you can monitor for unusually large or suspicious X3F files being processed or transferred.
Specific commands to detect the vulnerability or exploitation attempts are not provided in the available resources.
What immediate steps should I take to mitigate this vulnerability?
The primary mitigation step is to update LibRaw to the patched version released on April 6, 2026, which fixes the heap-based buffer overflow in the x3f_thumb_loader function.
Until the update can be applied, avoid processing untrusted or malicious Sigma/Foveon X3F RAW image files, especially those that might contain specially crafted thumbnails.
Additionally, if possible, disable or avoid using the -DUSE_X3FTOOLS compilation option or any functionality that invokes unpack_thumb() on X3F files.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.