High Cryptography exploit reference

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)

Published Sep 5, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: CERT-PL

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Mikrotik

Routeros

CVSS base

8.1

High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented mitigation — cert.pl (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Mikrotik Routeros).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the documented mitigations until a definitive fix is available.
Search available logs for exploit probes matching the vulnerability class (cryptography), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Mikrotik	Routeros	≥ 7.9 and < 7.23.4≥ 7.24 and < 7.24.2	Vulnerable	NIST National Vulnerability Database
Mikrotik	Routeros	≥ 7.24 and < 7.24.2≥ 7.9 and < 7.23.4	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

High

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
9.2	CVSS 4.0	Critical	—	—	cvd@cert.pl via NIST National Vulnerability Database
9.2	CVSS 4.0	Critical	—	—	CERT-PL via CVE Program (cve.org) e CISA ADP
8.1	CVSS 3.1	High	2.2	5.9	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-347 · Improper Verification of Cryptographic Signature

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Check TLS negotiations and unexpected certificates in the component’s traffic.

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · mikrotik/routeros
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
Fix documented
Oct 15, 2026 · NIST National Vulnerability Database
CVSS changed · 8.1
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 5, 2026 · CERT-PL

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

6 on the record

mikrotik.com/supportsec/september-2026-vulnerability/
Vendor Advisory, vendor-advisory, NIST National Vulnerability Database
cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploi
Mitigation, Third Party Advisory, technical-description, NIST National Vulnerability Database
forum.mikrotik.com/t/7-24-2-stable-is-released/272800
Release Notes, release-notes, NIST National Vulnerability Database
cert.pl/en/posts/2026/09/mikrotik-routeros-cve
Third Party Advisory, third-party-advisory, NIST National Vulnerability Database
forum.mikrotik.com/t/7-23-4-long-term-is-released/272801
Release Notes, release-notes, NIST National Vulnerability Database
npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt
Exploit, Third Party Advisory, exploit, NIST National Vulnerability Database

Elsewhere on this site

Mikrotik
every CVE for this vendor

Cryptography
same class

CWE-347
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-103903 MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation 3d
Critical CVE-2026-84411 MikroTik RouterOS Integer Underflow 13d
High CVE-2026-93345 MikroTik RouterOS < 7.25beta4 Improper Input Validation DoS via BGP Labelled-VPN NLRI 23d
High CVE-2026-89028 MikroTik RouterOS < 7.24 Heap Corruption via SMB1 SessionSetupAndX 29d
Medium CVE-2026-56719 MikroTik RouterOS < 7.24 Out-of-Bounds Read via SMB1 SessionSetupAndX 29d
Medium CVE-2026-89021 MikroTik RouterOS Path Traversal via Container OCI/tar Image Extraction Sep 14, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-67276 is "SSH user impersonation possible in Mikrotik RouterOS", rated High. It affects Routeros (Mikrotik); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.1 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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