CVE-2026-44637: saitoha libsixel · Integer Overflow or Wraparound
Affects saitoha libsixelSource CVE Database V5
Not known to be exploited · CVSS 7.1 High : upgrade to 1.8.7-r2 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.8.7-r2
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 May 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-r2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| saitohalibsixel | Affected
| Fixed in
|
GitHubsaitoha/libsixelpkg:github/saitoha/libsixelOther threats | Affected
| Fixed in– |
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AI-suggested
A fix is available in libsixel version 1.8.7-r2. Users and maintainers should upgrade to this version to remediate the vulnerability. Since the vendor advisory confirms the issue is fixed in 1.8.7-r2, applying this official fix is the recommended mitigation. No additional vendor guidance or temporary workarounds are provided.
Description
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a signed integer overflow in the SIXEL parser's image-buffer doubling loop can lead to an out-of-bounds heap write in sixel_decode_raw_impl. context->pos_x grows by repeat_count on every sixel character with no upper bound check. Once pos_x approaches INT_MAX, the expression "pos_x + repeat_count" used to size the image buffer overflows signed int. Depending on how the overflow wraps, the resize check that should reject oversized buffers can be bypassed, after which a subsequent write computes a large attacker-influenced offset into image->data and writes past the allocation. Reachable from any caller that decodes attacker-supplied SIXEL data, including img2sixel. This vulnerability is fixed in 1.8.7-r2.