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CVE-2026-31798: JumpServer Improper Certificate Validation in Custom SMS API Client

Analyzed
Published 13-03-2026Last modified 13-03-2026

Vulnerability summary

CVE-2026-31798 is a medium (CVSS 5.0) Improper Certificate Validation vulnerability in fit2cloud jumpserver. EPSS estimates a 0.10% chance of exploitation in the next 30 days, higher than 0.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.0/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.10%
0%100%
Low · -0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 13-03-2026
    PublishedVulnerability first disclosed.
  2. 13-03-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.10%

Chance of exploitation in the next 30 days

Percentile

1%

Versus all other CVEs

30-day change

Decrease -0.02 pp

From 0.12% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Fit2cloud1 product
Jumpserver1 product

2 vendors · 2 products

References

1 links