MikroTik RouterOS before 6.43.12 (stable) and 6.42.12 (long-term) is vulnerable to an intermediary vulnerability.

published 2019-02-20 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-13531

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 15.7%; EPSS 15.7% chance of exploitation in 30 days, percentile 96%
public exploits: 1; Exploit-DB

MikroTik RouterOS before 6.43.12 (stable) and 6.42.12 (long-term) is vulnerable to an intermediary vulnerability. The software will execute user defined network requests to both WAN and LAN clients. A remote unauthenticated attacker can use this vulnerability to bypass the router's firewall or for general network scanning activities.

Patch / fix

fixed in 1

mikrotik routeros 6.42.12, 6.43.12

Timeline

2019-02-20 Published
2019-02-21 First public exploit (EDB-46444)

Exploit prediction

15.70% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

EDB-46444 MikroTik RouterOS < 6.43.12 (stable) / < 6.42.12 (long-term) - Firewall and NAT Bypass remote, 2019-02-21
tenable.com https://www.tenable.com/security/research/tra-2019-07 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:P/I:N/A:N

Affected products

Tenable MikroTik RouterOS

Classification

Weakness

CWE-441 Unintended Proxy or Intermediary

References

exploit-db.com /exploits/46444/
exploit, third-party-advisory, vdb-entry
tenable.com /security/research/tra-2019-07
exploit, third-party-advisory
securityfocus.com /bid/107177
vdb-entry, third-party-advisory

Sources

CVE List CVE-2019-3924
NVD CVE-2019-3924

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.

Summary