CVE-2026-33019: CWE-125: Out-of-bounds Read in saitoha libsixel
libsixel versions prior to 1. 8. 7-r1 contain an integer overflow vulnerability in the --crop option handling of img2sixel. This flaw allows an out-of-bounds heap read when processing specially crafted crop arguments with positive coordinates up to INT_MAX, leading to a crash and potential information disclosure. The issue arises because the calculation of clip boundaries overflows and bypasses bounds checking, causing memory beyond the image buffer to be accessed. This vulnerability has been fixed in version 1. 8. 7-r1.
AI Analysis
Technical Summary
The vulnerability in libsixel (CVE-2026-33019) is an integer overflow that results in an out-of-bounds heap read during the handling of the --crop option in img2sixel. Specifically, when the crop coordinates include values up to INT_MAX, the addition of clip_w and clip_x overflows to a negative value, causing the bounds guard to be skipped. Consequently, an unclamped coordinate is passed to sixel_frame_clip() and then to clip(), which computes a source pointer outside the valid image buffer. This pointer is then used in memmove(), leading to a heap out-of-bounds read. An attacker can exploit this by supplying a crafted crop argument with any valid image, causing a reliable crash and possible information disclosure. The vulnerability is fixed in libsixel version 1.8.7-r1.
Potential Impact
Successful exploitation results in a heap out-of-bounds read, which can cause a crash (denial of service) and may lead to information disclosure. The vulnerability affects confidentiality and availability but does not impact integrity. The CVSS v3.1 score is 7.1 (high severity), reflecting local attack vector with low complexity, no privileges required, user interaction needed, unchanged scope, high confidentiality impact, no integrity impact, and high availability impact.
Mitigation Recommendations
A fix is available in libsixel version 1.8.7-r1. Users and administrators should upgrade to this version or later to remediate the vulnerability. No other mitigation or workaround is indicated in the available data.
CVE-2026-33019: CWE-125: Out-of-bounds Read in saitoha libsixel
Description
libsixel versions prior to 1. 8. 7-r1 contain an integer overflow vulnerability in the --crop option handling of img2sixel. This flaw allows an out-of-bounds heap read when processing specially crafted crop arguments with positive coordinates up to INT_MAX, leading to a crash and potential information disclosure. The issue arises because the calculation of clip boundaries overflows and bypasses bounds checking, causing memory beyond the image buffer to be accessed. This vulnerability has been fixed in version 1. 8. 7-r1.
CVSS v3.1
Score 7.1high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in libsixel (CVE-2026-33019) is an integer overflow that results in an out-of-bounds heap read during the handling of the --crop option in img2sixel. Specifically, when the crop coordinates include values up to INT_MAX, the addition of clip_w and clip_x overflows to a negative value, causing the bounds guard to be skipped. Consequently, an unclamped coordinate is passed to sixel_frame_clip() and then to clip(), which computes a source pointer outside the valid image buffer. This pointer is then used in memmove(), leading to a heap out-of-bounds read. An attacker can exploit this by supplying a crafted crop argument with any valid image, causing a reliable crash and possible information disclosure. The vulnerability is fixed in libsixel version 1.8.7-r1.
Potential Impact
Successful exploitation results in a heap out-of-bounds read, which can cause a crash (denial of service) and may lead to information disclosure. The vulnerability affects confidentiality and availability but does not impact integrity. The CVSS v3.1 score is 7.1 (high severity), reflecting local attack vector with low complexity, no privileges required, user interaction needed, unchanged scope, high confidentiality impact, no integrity impact, and high availability impact.
Mitigation Recommendations
A fix is available in libsixel version 1.8.7-r1. Users and administrators should upgrade to this version or later to remediate the vulnerability. No other mitigation or workaround is indicated in the available data.
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: 69deb96d82d89c981f0b1a0d
Added to database: 4/14/2026, 10:02:21 PM
Last enriched: 4/22/2026, 6:33:59 AM
Last updated: 5/29/2026, 7:18:26 AM
Views: 63
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