What is CVE-2026-100836?

CVE-2026-100836 is a medium-severity vulnerability in Edgelesssys Contrast, classified under Improper Validation of Array Index. CVSS score: 4.3/10. Published 2026-09-27.

How severe is CVE-2026-100836?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Edgelesssys Contrast

CVE-2026-100836

Contrast through 1.20.0 contains a panic vulnerability in the transit-engine endpoint's ciphertextContainer.UnmarshalJSON function that fails to validate decoded ciphertext length before slicing. An authenticated workload with a valid mesh certificate can trigger a runtime panic by submitting a short base64-encoded ciphertext, causing log spam and request failures without crashing the process.

Published 2026-09-27.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Edgelesssys Contrast

Weakness classification (CWE)

CWE-129 — Improper Validation of Array Index

References

github.com/edgelesssys/contrast/security/advisories/GHSA-3ccm-4qq2-5wrp (vendor-advisory)
www.vulncheck.com/advisories/edgeless-systems-contrast-through-1.20.0-denial-of… (third-party-advisory)

Frequently asked questions

What is CVE-2026-100836?: CVE-2026-100836 is a medium-severity vulnerability in Edgelesssys Contrast, classified under Improper Validation of Array Index. CVSS score: 4.3/10. Published 2026-09-27.
How severe is CVE-2026-100836?: Medium severity. CVSS v3 base score is 4.3 out of 10.