What is CVE-2021-30137?

CVE-2021-30137 is a high-severity vulnerability in Axiossystems Assyst, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 7.7/10. Published 2021-09-15.

How severe is CVE-2021-30137?

High severity. CVSS v3 base score is 7.7 out of 10.

XXE in Axiossystems Assyst

CVE-2021-30137

Assyst 10 SP7.5 has authenticated XXE leading to SSRF via XML unmarshalling. The application allows users to send JSON or XML data to the server. It was possible to inject malicious XML data through several access points.

Vulnerability class: XXE (XML External Entity)

Published 2021-09-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H.

EPSS exploit prediction

EPSS: 0.007 (51.9th percentile), scored 2026-10-04.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Axiossystems Assyst — versions 10

Weakness classification (CWE)

CWE-611 — Improper Restriction of XML External Entity Reference (XXE)

References

github.com/post-cyberlabs/CVE-Advisory/blob/main/CVE-2021-30137.pdf (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-30137?: CVE-2021-30137 is a high-severity vulnerability in Axiossystems Assyst, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 7.7/10. Published 2021-09-15.
How severe is CVE-2021-30137?: High severity. CVSS v3 base score is 7.7 out of 10.