CVE-2026-44636

HIGHNVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
7.4
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.4Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, signed integer overflow in sixel_encode_highcolor's allocation size calculation can lead to a heap buffer overflow. The public sixel_encode entry point validates only that width and height are greater than zero, with no upper bound. width and height are multiplied as plain int when computing the allocation size for paletted_pixels and normalized_pixels. Any caller that asks libsixel to encode a pixel buffer with width times height greater than INT_MAX (about 2.15 billion) will hit a wrapped allocation size; under the right wrap, the malloc succeeds with a buffer much smaller than the encoder expects, and the encoder writes past the end of the heap allocation. This vulnerability is fixed in 1.8.7-r2.

CVSS v3
7.4
EG Score
7.4(medium)
EG Risk
49(Track*)
EG Risk 49/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity74% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
1.2%
KEV
Not listed

Published

May 14, 2026

Last Modified

May 16, 2026

Advisory Details (1)

Auto-updated May 14, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

integer overflow in encoder · Advisory · saitoha/libsixel · GitHub

https://github.com/saitoha/libsixel/security/advisories/GHSA-hx93-w8p2-ffh5

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-25 14:18 UTCEPSS rescore
  2. 2026-07-24 14:17 UTCEPSS rescore
  3. 2026-07-23 14:18 UTCEPSS rescore
  4. 2026-07-23 03:15 UTCEG score recompute
  5. 2026-07-22 14:08 UTCEPSS rescore
  6. 2026-07-21 15:24 UTCEPSS rescore
  7. 2026-07-20 17:08 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-18 01:29 UTCOSV refresh
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-13 22:30 UTCEPSS rescore
  14. 2026-07-13 06:13 UTCEPSS rescore
  15. 2026-07-12 05:46 UTCEPSS rescore
  16. 2026-07-09 19:10 UTCEPSS rescore
  17. 2026-07-08 15:16 UTCEPSS rescore
  18. 2026-07-07 13:46 UTCEPSS rescore
  19. 2026-07-06 02:23 UTCEPSS rescore
  20. 2026-07-05 02:30 UTCEPSS rescore
  21. 2026-07-04 06:31 UTCEPSS rescore
  22. 2026-07-01 15:07 UTCEPSS rescore
  23. 2026-06-30 23:22 UTCEPSS rescore
  24. 2026-06-29 14:06 UTCEPSS rescore
  25. 2026-06-29 14:06 UTCEPSS rescore
Show 49 more
  1. 2026-06-28 14:07 UTCEPSS rescore
  2. 2026-06-28 04:56 UTCEPSS rescore
  3. 2026-06-27 03:08 UTCEPSS rescore
  4. 2026-06-23 21:33 UTCEPSS rescore
  5. 2026-06-22 14:25 UTCEPSS rescore
  6. 2026-06-22 14:25 UTCEPSS rescore
  7. 2026-06-19 19:25 UTCEPSS rescore
  8. 2026-06-18 17:52 UTCEPSS rescore
  9. 2026-06-18 17:52 UTCEPSS rescore
  10. 2026-06-17 17:53 UTCEPSS rescore
  11. 2026-06-16 17:52 UTCEPSS rescore
  12. 2026-06-15 17:49 UTCEPSS rescore
  13. 2026-06-13 23:00 UTCEPSS rescore
  14. 2026-06-12 23:12 UTCEPSS rescore
  15. 2026-06-12 23:12 UTCEPSS rescore
  16. 2026-06-11 14:00 UTCEPSS rescore
  17. 2026-06-10 22:18 UTCEPSS rescore
  18. 2026-06-10 13:22 UTCEPSS rescore
  19. 2026-06-10 13:22 UTCEPSS rescore
  20. 2026-06-08 14:17 UTCEPSS rescore
  21. 2026-06-08 14:17 UTCEPSS rescore
  22. 2026-06-07 15:25 UTCEPSS rescore
  23. 2026-06-07 15:25 UTCEPSS rescore
  24. 2026-06-06 13:47 UTCEPSS rescore
  25. 2026-06-06 13:47 UTCEPSS rescore
  26. 2026-06-05 22:47 UTCEPSS rescore
  27. 2026-06-05 06:10 UTCEPSS rescore
  28. 2026-06-05 06:10 UTCEPSS rescore
  29. 2026-06-04 13:12 UTCEPSS rescore
  30. 2026-06-04 13:12 UTCEPSS rescore
  31. 2026-06-02 20:13 UTCEPSS rescore
  32. 2026-06-01 13:52 UTCEPSS rescore
  33. 2026-06-01 13:52 UTCEPSS rescore
  34. 2026-05-31 22:30 UTCEPSS rescore
  35. 2026-05-31 22:30 UTCEPSS rescore
  36. 2026-05-31 00:16 UTCEPSS rescore
  37. 2026-05-31 00:16 UTCEPSS rescore
  38. 2026-05-29 13:44 UTCEPSS rescore
  39. 2026-05-29 13:44 UTCEPSS rescore
  40. 2026-05-28 13:44 UTCEPSS rescore
  41. 2026-05-28 13:44 UTCEPSS rescore
  42. 2026-05-27 13:40 UTCEPSS rescore
  43. 2026-05-27 13:40 UTCEPSS rescore
  44. 2026-05-26 13:44 UTCEPSS rescore
  45. 2026-05-26 07:18 UTCEPSS rescore
  46. 2026-05-21 22:43 UTCEPSS rescore
  47. 2026-05-20 22:38 UTCEPSS rescore
  48. 2026-05-20 12:12 UTCEG score recompute
  49. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-44636?
CVE-2026-44636 is a high vulnerability published on May 14, 2026. libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, signed integer overflow in sixelencodehighcolor's allocation size calculation can lead to a heap buffer overflow. The public sixelencode entry point validates only that width and height are greater than…
When was CVE-2026-44636 disclosed?
CVE-2026-44636 was first published in the National Vulnerability Database on May 14, 2026, with the most recent update on May 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44636 actively exploited?
CVE-2026-44636 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-44636?
CVE-2026-44636 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2026-44636?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44636, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-44636

Explore →

Is Your Infrastructure Affected by CVE-2026-44636?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs