# CVE-2023-36831: Junos OS: SRX Series: jbuf memory leak when SSL Proxy and UTM Web-Filtering is applied

> A memory leak in Junos OS SRX Series causes denial of service when SSL Proxy and UTM Web-Filtering are enabled, requiring a reboot to restore service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jul 2023
- **Updated:** 7 Nov 2024
- **Also known as:** GHSA-g6m3-8xg2-qjhj

## What is CVE-2023-36831?

CVE-2023-36831 is a high-severity denial of service vulnerability in Juniper Junos, published on 14 Jul 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An Improper Check or Handling of Exceptional Conditions vulnerability in the UTM (Unified Threat Management) Web-Filtering feature of Juniper Networks Junos OS on SRX Series causes a jbuf memory leak to occur when accessing certain websites, eventually leading to a Denial of Service (DoS) condition.  Service restoration is only possible by rebooting the system.

The jbuf memory leak only occurs in SSL Proxy and UTM Web-Filtering configurations.  Other products, platforms, and configurations are not affected by this vulnerability.

This issue affects Juniper Networks Junos OS on SRX Series:
22.2 versions prior to 22.2R3;
22.3 versions prior to 22.3R2-S1, 22.3R3;
22.4 versions prior to 22.4R1-S2, 22.4R2.

This issue does not affect Juniper Networks Junos OS versions prior to 22.2R2.

Weakness: CWE-703 (Improper Check or Handling of Exceptional Conditions)

## Which versions are affected by CVE-2023-36831?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2023-36831?

No fix has been published for CVE-2023-36831 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-36831 being exploited?

There is no known exploitation of CVE-2023-36831 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-2023-36831 and fix it if it is affected.

What it is: CVE-2023-36831 is a high-severity denial of service vulnerability in Juniper Junos, published on 14 Jul 2023. 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-2023-36831 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-2023-36831/ (Markdown: https://insights.sbomify.com/CVE-2023-36831/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-36831
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-36831
- OSV: https://osv.dev/vulnerability/CVE-2023-36831

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-36831/
Summaries are generated and may contain mistakes; the official description above is the record.