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

> Attackers can intercept MFA codes via improper certificate validation in the Custom SMS API, enabling account takeover.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 13 Mar 2026
- **Updated:** 13 Mar 2026
- **Also known as:** GHSA-26pj-mmxw-w3w7

## What is CVE-2026-31798?

CVE-2026-31798 is a medium-severity vulnerability in jumpserver, published on 13 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-31798?

It affects 1 product.


Products: Fit2cloud Jumpserver.

## How do I fix CVE-2026-31798?

No fix has been published for CVE-2026-31798 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-31798 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31798 exists.

## Other vulnerabilities in jumpserver

- [CVE-2024-40628](https://insights.sbomify.com/CVE-2024-40628/): Arbitrary File Read in Ansible Playbooks in Jumpserver (critical 10.0)
- [CVE-2024-40629](https://insights.sbomify.com/CVE-2024-40629/): Arbitrary File Write in Ansible Playbooks leads to RCE in Jumpserver (critical 10.0)
- [CVE-2024-29201](https://insights.sbomify.com/CVE-2024-29201/): JumpServer's insecure Ansible playbook validation leads to RCE in Celery (critical 10.0)
- [CVE-2024-29202](https://insights.sbomify.com/CVE-2024-29202/): JumpServer vulnerable to Jinja2 template injection in Ansible leads to RCE in Celery (critical 10.0)
- [CVE-2023-48193](https://insights.sbomify.com/CVE-2023-48193/): Security feature bypass in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31798 and fix it if it is affected.

What it is: CVE-2026-31798 is a medium-severity vulnerability in jumpserver, published on 13 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31798 exists.

Affected product: jumpserver. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-31798/ (Markdown: https://insights.sbomify.com/CVE-2026-31798/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31798
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31798
- OSV: https://osv.dev/vulnerability/CVE-2026-31798

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31798/
Summaries are generated and may contain mistakes; the official description above is the record.