CVE-2018-18556

CRITICALNVD 9.99.9—
EchelonGraph scoreMEDIUM confidence

Score 9.9 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-13. NVD baseline CVSS 9.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
9.9
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 15%CVSS: 9.9Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A privilege escalation issue was discovered in VyOS 1.1.8. The default configuration also allows operator users to execute the pppd binary with elevated (sudo) permissions. Certain input parameters are not properly validated. A malicious operator user can run the binary with elevated permissions and leverage its improper input validation condition to spawn an attacker-controlled shell with root privileges.

CVSS v3
9.9
EG Score
9.9(medium)
EPSS
96.4%
KEV
Not listed

Published

December 17, 2018

Last Modified

November 21, 2024

Advisory Details (3)

Auto-updated Jun 29, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

The "operator" level is proved insecure and will be removed in the next releases

https://blog.vyos.io/the-operator-level-is-proved-insecure-and-will-be-removed-in-the-next-releases
generic

CVE-2018-18556 - VyOS Privilege escalation via sudo pppd for operator users | Rich Mirch

https://blog.mirch.io/2018/11/05/cve-2018-18556-vyos-privilege-escalation-via-sudo-pppd-for-operator-users/
generic

Packet Storm

http://packetstormsecurity.com/files/159234/VyOS-restricted-shell-Escape-Privilege-Escalation.html

Data Freshness Timeline

(refreshed 13× in last 7d / 43× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-07 13:42 UTCEPSS rescore
  2. 2026-07-07 13:42 UTCEPSS rescore
  3. 2026-07-06 16:24 UTCEPSS rescore
  4. 2026-07-06 16:24 UTCEPSS rescore
  5. 2026-07-06 02:20 UTCEPSS rescore
  6. 2026-07-05 02:27 UTCEPSS rescore
  7. 2026-07-04 06:28 UTCEPSS rescore
  8. 2026-07-04 06:28 UTCEPSS rescore
  9. 2026-07-02 16:54 UTCEPSS rescore
  10. 2026-07-01 15:03 UTCEPSS rescore
  11. 2026-07-01 15:03 UTCEPSS rescore
  12. 2026-06-30 23:20 UTCEPSS rescore
  13. 2026-06-30 23:19 UTCEPSS rescore
  14. 2026-06-29 14:03 UTCEPSS rescore
  15. 2026-06-28 14:04 UTCEPSS rescore
  16. 2026-06-28 04:53 UTCEPSS rescore
  17. 2026-06-28 04:53 UTCEPSS rescore
  18. 2026-06-27 03:06 UTCEPSS rescore
  19. 2026-06-27 03:06 UTCEPSS rescore
  20. 2026-06-25 13:47 UTCEPSS rescore
  21. 2026-06-25 13:47 UTCEPSS rescore
  22. 2026-06-24 14:02 UTCEPSS rescore
  23. 2026-06-24 14:02 UTCEPSS rescore
  24. 2026-06-23 21:30 UTCEPSS rescore
  25. 2026-06-23 21:30 UTCEPSS rescore
Show 37 more
  1. 2026-06-23 21:30 UTCEPSS rescore
  2. 2026-06-21 01:57 UTCEPSS rescore
  3. 2026-06-21 01:57 UTCEPSS rescore
  4. 2026-06-19 19:23 UTCEPSS rescore
  5. 2026-06-19 19:23 UTCEPSS rescore
  6. 2026-06-18 17:50 UTCEPSS rescore
  7. 2026-06-18 17:50 UTCEPSS rescore
  8. 2026-06-17 17:50 UTCEPSS rescore
  9. 2026-06-17 17:50 UTCEPSS rescore
  10. 2026-06-16 17:50 UTCEPSS rescore
  11. 2026-06-16 17:50 UTCEPSS rescore
  12. 2026-06-15 17:45 UTCEPSS rescore
  13. 2026-06-14 23:15 UTCEPSS rescore
  14. 2026-06-14 23:14 UTCEPSS rescore
  15. 2026-06-12 23:09 UTCEPSS rescore
  16. 2026-06-12 23:09 UTCEPSS rescore
  17. 2026-06-11 13:57 UTCEPSS rescore
  18. 2026-06-10 22:16 UTCEPSS rescore
  19. 2026-06-05 22:45 UTCEPSS rescore
  20. 2026-06-05 22:45 UTCEPSS rescore
  21. 2026-06-05 06:08 UTCEPSS rescore
  22. 2026-06-05 06:08 UTCEPSS rescore
  23. 2026-06-04 13:10 UTCEPSS rescore
  24. 2026-06-02 20:11 UTCEPSS rescore
  25. 2026-06-02 20:11 UTCEPSS rescore
  26. 2026-06-01 13:50 UTCEPSS rescore
  27. 2026-06-01 13:50 UTCEPSS rescore
  28. 2026-05-31 00:14 UTCEPSS rescore
  29. 2026-05-31 00:14 UTCEPSS rescore
  30. 2026-05-28 13:42 UTCEPSS rescore
  31. 2026-05-28 13:42 UTCEPSS rescore
  32. 2026-05-28 00:13 UTCEG score recompute
  33. 2026-05-28 00:13 UTCGHSA enrichment
  34. 2026-05-27 13:38 UTCEPSS rescore
  35. 2026-05-27 13:38 UTCEPSS rescore
  36. 2026-05-26 13:42 UTCEPSS rescore
  37. 2026-05-26 13:42 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Metasploit module). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Metasploitexploit/linux/ssh/vyos_restricted_shell_privesc✓ verified
    First seen Nov 5, 2018

    VyOS restricted-shell Escape and Privilege Escalation

    Open source ↗

Frequently asked(5)

What is CVE-2018-18556?
CVE-2018-18556 is a critical vulnerability published on December 17, 2018. A privilege escalation issue was discovered in VyOS 1.1.8. The default configuration also allows operator users to execute the pppd binary with elevated (sudo) permissions. Certain input parameters are not properly validated. A malicious operator user can run the binary with elevated permissions…
When was CVE-2018-18556 disclosed?
CVE-2018-18556 was first published in the National Vulnerability Database on December 17, 2018, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-18556 actively exploited?
CVE-2018-18556 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 96.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2018-18556?
CVE-2018-18556 has a CVSS v3 base score of 9.9 (NVD).
How do I remediate CVE-2018-18556?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-18556, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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