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Fencer Vulns
critical 9.8

CVE-2017-20149 json

The Mikrotik RouterOS web server allows memory corruption in releases before Stable 6.38.5 and Long-term 6.37.5, aka Chimay-Red.

published 2022-10-15 4 y ago modified 2026-06-17 4 mo ago also EUVD-2017-11155

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

The Mikrotik RouterOS web server allows memory corruption in releases before Stable 6.38.5 and Long-term 6.37.5, aka Chimay-Red. A remote and unauthenticated user can trigger the vulnerability by sending a crafted HTTP request. An attacker can use this vulnerability to execute arbitrary code on the affected system, as exploited in the wild in mid-2017 and later.

Patch / fix

  • mikrotik routeros 6.37.5, 6.38.5

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
17 mo ago

Exploit prediction

2.53% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/BigNerd95/Chimay-Red referenced PoC, tagged "exploit" by a source, unverified
  • bleepingcomputer.com https://www.bleepingcomputer.com/news/security/hajime-botnet-makes-a-comeback-with-massive-scan-for-mikrotik-routers/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.