CVE-2026-33023: CWE-416: Use After Free in saitoha libsixel
libsixel versions prior to 1. 8. 7-r1, when built with the --with-gdk-pixbuf2 option, contain a use-after-free vulnerability in the load_with_gdkpixbuf() function. This occurs because the cleanup code incorrectly frees a reference-counted object without respecting its reference count, leading to dangling pointers. An attacker can exploit this by supplying a crafted image to trigger memory corruption, potentially resulting in information disclosure or code execution. The issue has been fixed in version 1. 8. 7-r1.
AI Analysis
Technical Summary
libsixel is a SIXEL encoder/decoder library. In versions before 1.8.7-r1, a use-after-free vulnerability exists in load_with_gdkpixbuf() due to inconsistent cleanup strategies: the code manually frees a sixel_frame_t object created with reference counting without consulting the reference count. This leads to dangling pointers when callbacks retain references, causing use-after-free errors confirmed by AddressSanitizer. An attacker can trigger this by providing crafted images to applications linked with libsixel built with gdk-pixbuf2 support. The vulnerability is tracked as CVE-2026-33023 with a CVSS 3.1 score of 7.8 (high severity).
Potential Impact
Successful exploitation can lead to information disclosure, memory corruption, or arbitrary code execution in applications using vulnerable libsixel versions with gdk-pixbuf2 support. The vulnerability arises from a use-after-free condition that can be reliably triggered by crafted image files.
Mitigation Recommendations
This vulnerability has been fixed in libsixel version 1.8.7-r1. Users and developers should upgrade to this version or later to remediate the issue. No official patch links were provided, but upgrading to the fixed version is the recommended action. Since this is not a cloud service, remediation depends on updating the affected software. Patch status is not explicitly confirmed beyond the stated fixed version; verify with the vendor or project repository for the latest updates.
CVE-2026-33023: CWE-416: Use After Free in saitoha libsixel
Description
libsixel versions prior to 1. 8. 7-r1, when built with the --with-gdk-pixbuf2 option, contain a use-after-free vulnerability in the load_with_gdkpixbuf() function. This occurs because the cleanup code incorrectly frees a reference-counted object without respecting its reference count, leading to dangling pointers. An attacker can exploit this by supplying a crafted image to trigger memory corruption, potentially resulting in information disclosure or code execution. The issue has been fixed in version 1. 8. 7-r1.
CVSS v3.1
Score 7.8high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
libsixel is a SIXEL encoder/decoder library. In versions before 1.8.7-r1, a use-after-free vulnerability exists in load_with_gdkpixbuf() due to inconsistent cleanup strategies: the code manually frees a sixel_frame_t object created with reference counting without consulting the reference count. This leads to dangling pointers when callbacks retain references, causing use-after-free errors confirmed by AddressSanitizer. An attacker can trigger this by providing crafted images to applications linked with libsixel built with gdk-pixbuf2 support. The vulnerability is tracked as CVE-2026-33023 with a CVSS 3.1 score of 7.8 (high severity).
Potential Impact
Successful exploitation can lead to information disclosure, memory corruption, or arbitrary code execution in applications using vulnerable libsixel versions with gdk-pixbuf2 support. The vulnerability arises from a use-after-free condition that can be reliably triggered by crafted image files.
Mitigation Recommendations
This vulnerability has been fixed in libsixel version 1.8.7-r1. Users and developers should upgrade to this version or later to remediate the issue. No official patch links were provided, but upgrading to the fixed version is the recommended action. Since this is not a cloud service, remediation depends on updating the affected software. Patch status is not explicitly confirmed beyond the stated fixed version; verify with the vendor or project repository for the latest updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-03-17T17:22:14.667Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69debcd482d89c981f0dfd18
Added to database: 4/14/2026, 10:16:52 PM
Last enriched: 4/22/2026, 6:34:10 AM
Last updated: 5/29/2026, 7:19:06 PM
Views: 56
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