CVE-2026-33023: CWE-416: Use After Free in saitoha libsixel
A use-after-free vulnerability exists in libsixel versions prior to 1. 8. 7-r1 when built with the --with-gdk-pixbuf2 option. The issue arises from inconsistent cleanup of sixel_frame_t objects, leading to dangling pointers after callbacks retain references. An attacker supplying a crafted image can trigger this vulnerability, potentially causing information disclosure, memory corruption, or code execution. The vulnerability has been fixed in version 1. 8. 7-r1.
AI Analysis
Technical Summary
libsixel, a SIXEL encoder/decoder, contains a use-after-free vulnerability in the load_with_gdkpixbuf() function of loader.c in versions before 1.8.7-r1. The problem stems from a mismatch in cleanup strategies: the sixel_frame_t object is manually freed without reference count checks despite being created with a refcounted constructor. This leads to dangling pointers when callbacks retain references, causing use-after-free conditions confirmed by AddressSanitizer. An attacker can exploit this by providing crafted images to applications using libsixel 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
Exploitation of this use-after-free vulnerability can lead to information disclosure, memory corruption, or arbitrary code execution in applications using vulnerable libsixel versions built with gdk-pixbuf2 support. The vulnerability requires local access (AV:L) and user interaction (UI:R) but does not require privileges (PR:N).
Mitigation Recommendations
This vulnerability has been fixed in libsixel version 1.8.7-r1. Users and maintainers should upgrade to version 1.8.7-r1 or later to remediate this issue. No official patch links were provided in the input, but the vendor's release notes or repository should be consulted for the fixed version. Until upgraded, avoid processing untrusted images with vulnerable libsixel builds.
CVE-2026-33023: CWE-416: Use After Free in saitoha libsixel
Description
A use-after-free vulnerability exists in libsixel versions prior to 1. 8. 7-r1 when built with the --with-gdk-pixbuf2 option. The issue arises from inconsistent cleanup of sixel_frame_t objects, leading to dangling pointers after callbacks retain references. An attacker supplying a crafted image can trigger this vulnerability, potentially causing information disclosure, memory corruption, or code execution. The vulnerability has been fixed in version 1. 8. 7-r1.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
libsixel, a SIXEL encoder/decoder, contains a use-after-free vulnerability in the load_with_gdkpixbuf() function of loader.c in versions before 1.8.7-r1. The problem stems from a mismatch in cleanup strategies: the sixel_frame_t object is manually freed without reference count checks despite being created with a refcounted constructor. This leads to dangling pointers when callbacks retain references, causing use-after-free conditions confirmed by AddressSanitizer. An attacker can exploit this by providing crafted images to applications using libsixel 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
Exploitation of this use-after-free vulnerability can lead to information disclosure, memory corruption, or arbitrary code execution in applications using vulnerable libsixel versions built with gdk-pixbuf2 support. The vulnerability requires local access (AV:L) and user interaction (UI:R) but does not require privileges (PR:N).
Mitigation Recommendations
This vulnerability has been fixed in libsixel version 1.8.7-r1. Users and maintainers should upgrade to version 1.8.7-r1 or later to remediate this issue. No official patch links were provided in the input, but the vendor's release notes or repository should be consulted for the fixed version. Until upgraded, avoid processing untrusted images with vulnerable libsixel builds.
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: 4/14/2026, 10:31:51 PM
Last updated: 4/14/2026, 11:32:42 PM
Views: 4
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