CVE-2026-33018
7.0 · HIGHOverview
CVE-2026-33018 is a high-severity vulnerability affecting saitoha libsixel. It was published on April 14, 2026 and has a CVSS 3.1 base score of 7.0 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.0, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical Description
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a Use-After-Free vulnerability via the load_gif() function in fromgif.c, where a single sixel_frame_t object is reused across all frames of an animated GIF and gif_init_frame() unconditionally frees and reallocates frame->pixels between frames without consulting the object's reference count. Because the public API explicitly provides sixel_frame_ref() to retain a frame and sixel_frame_get_pixels() to access the raw pixel buffer, a callback following this documented usage pattern will hold a dangling pointer after the second frame is decoded, resulting in a heap use-after-free confirmed by ASAN. Any application using sixel_helper_load_image_file() with a multi-frame callback to process user-supplied animated GIFs is affected, with a reliable crash as the minimum impact and potential for code execution. This issue has been fixed in version 1.8.7-r1.
Remediation
Check the references section for vendor advisories and patches from saitoha. Update libsixel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| saitoha | libsixel | >= 0, < 1.8.7-r1 | Affected |
Frequently Asked Questions
What is CVE-2026-33018?
CVE-2026-33018 is a high-severity vulnerability affecting saitoha libsixel. It was published on April 14, 2026 and has a CVSS 3.1 base score of 7.0 (HIGH).
How severe is CVE-2026-33018?
This vulnerability has a CVSS 3.1 base score of 7.0, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-33018?
Check the references section for vendor advisories and patches from saitoha. Update libsixel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-33018?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-33018 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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