What is CVE-2026-31798?

CVE-2026-31798 is a medium-severity vulnerability in Fit2cloud Jumpserver, classified under Improper Certificate Validation. CVSS score: 5.0/10. Published 2026-03-13.

How severe is CVE-2026-31798?

Medium severity. CVSS v3 base score is 5.0 out of 10.

Vulnerability in Fit2cloud Jumpserver

CVE-2026-31798

JumpServer is an open source bastion host and an operation and maintenance security audit system. Prior to v4.10.16-lts, JumpServer improperly validates certificates in the Custom SMS API Client. When JumpServer sends MFA/OTP codes via Custom SMS API, an attacker can intercept the request and capture the verification code BEFORE it reaches the user's phone. This vulnerability is fixed in v4.10.16-lts.

Vulnerability class: Improper Certificate Validation

Published 2026-03-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.001 (2.2th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000

Affected products

Fit2cloud Jumpserver
Jumpserver — versions < 4.10.16-lts

Weakness classification (CWE)

CWE-295 — Improper Certificate Validation

References

github.com/jumpserver/jumpserver/security/advisories/GHSA-26pj-mmxw-w3w7 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-31798?: CVE-2026-31798 is a medium-severity vulnerability in Fit2cloud Jumpserver, classified under Improper Certificate Validation. CVSS score: 5.0/10. Published 2026-03-13.
How severe is CVE-2026-31798?: Medium severity. CVSS v3 base score is 5.0 out of 10.