# CVE-2024-30391: Auth bypass in Junos OS

> Attackers can bypass IPsec authentication on Juniper MX and SRX devices using specific HMAC algorithms, allowing unauthenticated traffic modification or denial of service.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Apr 2024
- **Updated:** 9 Aug 2024
- **Also known as:** GHSA-vpfm-675m-rfm8

## What is CVE-2024-30391?

CVE-2024-30391 is a medium-severity authentication bypass vulnerability in Juniper Junos, published on 12 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A Missing Authentication for Critical Function vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series with SPC3, and SRX Series allows an unauthenticated network-based attacker to cause limited impact to the integrity or availability of the device.

If a device is configured with IPsec authentication algorithm hmac-sha-384 or hmac-sha-512, tunnels are established normally but for traffic traversing the tunnel no authentication information is sent with the encrypted data on egress, and no authentication information is expected on ingress. So if the peer is an unaffected device transit traffic is going to fail in both directions. If the peer is an also affected device transit traffic works, but without authentication, and configuration and CLI operational commands indicate authentication is performed.
This issue affects Junos OS:

  *  All versions before 20.4R3-S7,
  *  21.1 versions before 21.1R3, 
  *  21.2 versions before 21.2R2-S1, 21.2R3, 
  *  21.3 versions before 21.3R1-S2, 21.3R2.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2024-30391?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2024-30391?

No fix has been published for CVE-2024-30391 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-30391 being exploited?

There is no known exploitation of CVE-2024-30391 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos

- [CVE-2023-36845](https://insights.sbomify.com/CVE-2023-36845/): Juniper Junos OS EX Series and SRX Series PHP External Variable Modification (critical 9.8, exploited in the wild)
- [CVE-2020-1631](https://insights.sbomify.com/CVE-2020-1631/): Juniper Junos OS Path Traversal (high 8.8, exploited in the wild)
- [CVE-2025-21590](https://insights.sbomify.com/CVE-2025-21590/): Juniper Junos OS Improper Isolation or Compartmentalization (medium 6.7, exploited in the wild)
- [CVE-2023-36851](https://insights.sbomify.com/CVE-2023-36851/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild)
- [CVE-2023-36844](https://insights.sbomify.com/CVE-2023-36844/): Juniper Junos OS EX Series PHP External Variable Modification (medium 5.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-30391 and fix it if it is affected.

What it is: CVE-2024-30391 is a medium-severity authentication bypass vulnerability in Juniper Junos, published on 12 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-30391 in the wild and no public exploit code.

Affected product: Juniper Junos. 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-2024-30391/ (Markdown: https://insights.sbomify.com/CVE-2024-30391/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-30391
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-30391
- OSV: https://osv.dev/vulnerability/CVE-2024-30391

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-30391/
Summaries are generated and may contain mistakes; the official description above is the record.