CVE-2026-33020: saitoha libsixel · Heap-based Buffer Overflow
Affects saitoha libsixelSource CVE Database V5
Not known to be exploited · CVSS 7.1 High : upgrade to 1.8.7-r1 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.8.7-r1
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 14 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade saitoha libsixel to 1.8.7-r1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| saitohalibsixel | Affected
| Fixed in
|
GitHubsaitoha/libsixelpkg:github/saitoha/libsixelOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability has been fixed in libsixel version 1.8.7-r1. Users and administrators should upgrade to version 1.8.7-r1 or later to remediate this issue. No other mitigation or workaround is specified. Patch status is confirmed by the vendor's fix in 1.8.7-r1.
Description
libsixel versions prior to 1.8.7-r1 contain a heap-based buffer overflow vulnerability caused by an integer overflow in the sixel_frame_convert_to_rgb888() function. This overflow leads to an undersized heap allocation and invalid pointer arithmetic when processing large palettised images, resulting in heap corruption. An attacker can exploit this by supplying a specially crafted large palettised PNG file, potentially causing a crash or arbitrary code execution. The issue is fixed in version 1.8.7-r1.