# CVE-2026-57021: Junos OS: SRX Series: If VPN compliance-check is configured an attacker can cause http-gk process crash

> An unauthenticated attacker can crash the http-gk process on Juniper SRX devices with VPN compliance checks, causing a denial of service.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/AU:Y/R:A/RE:M`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jul 2026
- **Updated:** 10 Jul 2026
- **Also known as:** GHSA-h2m8-76wp-v324

## What is CVE-2026-57021?

CVE-2026-57021 is a medium-severity memory corruption vulnerability in Juniper Junos, published on 9 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An Out-of-bounds Write vulnerability in the http-gatekeeper (http-gk) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).

If an SRX Series device is configured for remote-access VPN with pre-logon compliance check, a network-based attacker sending specifically formatted requests can trigger an out of bounds write leading to an http-gk process crash. This crash leads to unavailability of all services depending on the [ system services web-management ] configuration (like J-Web, remote access VPN and firewall authentication) until the process automatically restarts.

This issue affects Junos OS on SRX Series:

  *  23.2 versions before 23.2R2-S7,
  *  23.4 versions before 23.4R2-S8,
  *  24.2 versions before 24.2R2-S4,
  *  24.4 versions before 24.4R2-S4,
  *  25.2 versions before 25.2R2,
  *  25.4 versions before 25.4R1-S1, 25.4R2.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-57021?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2026-57021?

No fix has been published for CVE-2026-57021 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-57021 being exploited?

There is no known exploitation of CVE-2026-57021 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-2026-57021 and fix it if it is affected.

What it is: CVE-2026-57021 is a medium-severity memory corruption vulnerability in Juniper Junos, published on 9 Jul 2026. 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-2026-57021 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-2026-57021/ (Markdown: https://insights.sbomify.com/CVE-2026-57021/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57021
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57021
- OSV: https://osv.dev/vulnerability/CVE-2026-57021

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-57021/
Summaries are generated and may contain mistakes; the official description above is the record.