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CVE Record

CVE-2026-67276: SSH user impersonation possible in Mikrotik RouterOS

RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue affects only 7.x branch was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable)

CriticalCVSS 9.2Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

Affected MikroTik RouterOS 7.x devices may let an unauthenticated network attacker impersonate a user configured with an RSA SSH key. Successful abuse could provide that user's SSH command access without possessing the private key, putting device configuration, traffic control, and availability at risk.

Executive priority

Treat reachable affected routers as an emergency remediation item. Prioritize internet-facing SSH, privileged RSA-key users, and devices controlling critical connectivity. Upgrade promptly, restrict management access during remediation, and investigate unexplained SSH sessions or configuration changes.

Technical view

RouterOS compares an offered RSA key's type and modulus with the authorized key but omits the exponent. It then verifies the signature using the client-supplied key. An attacker who knows an authorized modulus may exploit this mismatch to authenticate without the corresponding private key. The issue is classified as CWE-347 and scored CVSS 4.0 9.2.

Likely exposure

Exposure requires RouterOS 7.x, SSH accessibility, and an authorized user using an RSA public key. Internet-accessible SSH substantially increases reachability. The bundle specifically lists versions 7.9 and 7.24, but does not provide a complete affected-version matrix; verify every 7.x deployment against MikroTik guidance.

Exploitation context

The supplied bundle does not conclusively establish active exploitation of CVE-2026-67276, and it is not listed as KEV here. Exploitation requires knowledge of an authorized RSA modulus and is rated high complexity, but successful authentication could provide full command access available to the impersonated user.

Researcher notes

The authentication flaw is an incomplete RSA public-key comparison: modulus and type are matched, but exponent is not. Signature verification trusts the supplied key, breaking proof of private-key possession. The bundle names fixed Long-term and Stable releases but lacks a complete version matrix, confirmed indicators, and definitive exploitation evidence.

Mitigation direction

  • Upgrade Long-term installations to RouterOS 7.23.4 or later.
  • Upgrade Stable installations to RouterOS 7.24.2 or later.
  • Until upgraded, restrict SSH access to trusted management networks.
  • Check MikroTik guidance for any additional branch-specific instructions.

Validation and detection

  • Inventory all RouterOS 7.x devices and record their release channels and versions.
  • Identify devices permitting SSH and users authorized with RSA public keys.
  • Confirm Long-term devices run 7.23.4 or later.
  • Confirm Stable devices run 7.24.2 or later.
  • Review SSH authentication and configuration-change records for unexplained privileged activity.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-347: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-67276 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.2 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.2CVSS 4.0CriticalCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——CERT-PL

Vulnerability scoring details

Base CVSS 4.0 score

9.2Critical
CVSS 4.0 vector shape for CVE-2026-67276Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MikrotikRouterOS7.24, 7.9unaffected
Weakness

CWE details

CWE-347

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-347 · source CWE mapping

Improper Verification of Cryptographic Signature

Improper Verification of Cryptographic Signature represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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