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MikroTik routers

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Hackers exploit new MikroTik RouterOS flaws to hijack routers

Attackers actively exploit a MikroTik RouterOS SSH authentication bypass and privilege escalation chain, dubbed MikroTrick, to fully hijack internet-exposed routers.

Poland's CERT, with help from GPT-5.5-cyber and GPT-5.6-sol, discovered and confirmed active exploitation of a MikroTik RouterOS chain dubbed MikroTrick: SSH authentication bypass CVE-2026-67276 (incomplete RSA public key validation) chained with privilege escalation CVE-2026-86060 (crafted usernames granting full administrative privileges). A third flaw, CVE-2026-67277, allows unauthenticated kernel memory leaks or router crashes via the bandwidth-test service. Fixes shipped September 3 in RouterOS 7.25beta3, 7.24.2, 7.23.4, and 6.49.21, adding a startup compromise-detection mechanism. Shadowserver data showed 122,500 MikroTik devices with exposed SSH interfaces as of September 5, and the CERT published IoCs including two attacker IP addresses.

Related CVEs

  • Argument-Injection Flaw in MikroTik RouterOS SSH Login Enables Privilege Escalation
    CVE-2026-86060 is an argument-injection flaw (CWE-88) in MikroTik RouterOS's SSH login path: when a login supplies a username beginning with a prohibited character, the RouterOS login helper mishandles the argument, allowing the trusted RouterOS policy mask to be changed and privileges to be escalated. An unauthenticated attacker only needs the ability to reach the router's SSH service, since exploitation happens during the SSH login process itself. By altering the policy mask the attacker gains elevated rights on the device, and news reports indicate attackers have used this technique — including logins with usernames such as '-2' — as part of chains that take over routers without needing a password. Any RouterOS deployment running versions before the fixes (6.49.21 Long-term, 7.23.4 Long-term, 7.24.2 Stable) with SSH enabled or reachable is affected, with internet-exposed SSH at highest risk. Multiple outlets report the RouterOS flaws are being actively exploited in the wild, although no public proof-of-concept is known and the flaw is not yet in CISA KEV.
    · MikroTik RouterOS v6 (Long-term channel) versions prior to 6.49.21 (fixed in 6.49.21) · MikroTik RouterOS v7 (Long-term channel) versions prior to 7.23.4 (fixed in 7.23.4) KEV PoC ×2mass
  • Unauthenticated Kernel Crash and Memory Leak in MikroTik RouterOS btest
    CVE-2026-67277 is a missing-authentication flaw (CWE-306) in the bandwidth-test (btest) service of MikroTik RouterOS: the service accepts a "related" btest connection before the primary session has completed authentication, so an unauthenticated remote client can start an IPv4 UDP bandwidth test. When the test runs with "random-data=false", the sender transmits an uninitialized tail from a kernel packet buffer, leaking a small amount of kernel memory, and a separate unchecked, inverted packet-size interval causes an unsigned integer underflow that produces anomalously large fragmented output capable of restarting the RouterOS kernel. An unauthenticated network attacker therefore gains limited information disclosure and, more significantly, a remote denial of service through repeated router crashes, with no credentials or user interaction required (CVSS 4.0: 8.8 High). Any MikroTik device running an unpatched RouterOS version with the bandwidth-test server enabled and reachable from an untrusted network is affected. No public PoC or CISA KEV listing exists for this CVE and EPSS is low (0.4%), but it is part of the batch of RouterOS fixes in MikroTik advisory AV26-887 that attackers have recently chained to hijack routers, so in-the-wild exploitation of the flaw set is reported.
    · MikroTik RouterOS (Long-term channel, v6) All versions prior to 6.49.21 (fixed in 6.49.21) · MikroTik RouterOS (Long-term channel, v7) All versions prior to 7.23.4 (fixed in 7.23.4) KEV PoC mass
  • SSH RSA Authorized-Key Bypass in MikroTik RouterOS 7.x
    MikroTik RouterOS 7.x fails to compare the complete RSA public key when matching an SSH authentication attempt against an authorized user key, checking the key type and modulus but omitting the exponent. Because RouterOS verifies the signature against the client-supplied key, an attacker who knows the modulus of an authorized RSA key can present a key with exponent 1 and a forged signature and be accepted as that user without possessing the private key. Successful exploitation opens an SSH command channel as the target user, giving the attacker control of the router without a password or key. Only the RouterOS 7.x branch is affected, with fixes released in 7.23.4 (Long-term) and 7.24.2 (Stable). A public proof-of-concept is available and related reporting describes active campaigns hijacking MikroTik routers using chained RouterOS flaws, though this CVE is not in CISA KEV and its 30-day EPSS probability is low (0.2%).
    · MikroTik RouterOS 7.x branch prior to 7.23.4 (Long-term) and 7.24.2 (Stable)mass

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