Intel

CVE-2026-67276

RouterOS vergleicht bei der Abgleichung einer SSH-Authentifizierungsanfrage mit einem autorisierten Benutzerschlüssel nicht den vollständ… (CVE-2026-67276)

criticalPoCEPSS 0.2 %

Beschreibung

RouterOS vergleicht bei der Abgleichung einer SSH-Authentifizierungsanfrage mit einem autorisierten Benutzerschlüssel nicht den vollständigen RSA-Publikschlüssel, sondern überprüft nur den Schlüsseltyp und den Modulus und übersieht dabei den Exponenten. Da die Signaturüberprüfung den vom Client bereitgestellten Schlüssel verwendet, kann ein Angreifer, der einen autorisierten RSA-Modulus kennt, einen Schlüssel mit dem Exponenten eins liefern, eine gültige Signatur fälschen und über einen SSH-Befehlskanal als Zielbenutzer ohne den privaten Schlüssel agieren. Dieses Problem wurde in den Versionen behoben: 6.49.21 (Langzeit), 7.23.4 (Langzeit) und 7.24.2 (Stabil).

Quelle: CVELISTV5NVDEUVD

Metriken

Severity
critical
Priority-Score
85.29
KEV-Status
—
Exploit-Reife
PoC (öffentlich gemeldet)
XIEM Effective CVSS
9.2
Quelle: cna-v4
CVSS v3
—
CVSS v4
9.2
EPSS-Perzentil
15.5 %
Erhöht — CVE ist relevanter als mindestens 10 % der heute bewerteten CVEs.
EPSS-Score
0.2 %
Niedrig — Modell schätzt < 1 % Ausnutzungs-Wahrscheinlichkeit.
Veröffentlicht
2026-09-05 20:00 UTC
CWE
CWE-347

Weakness-Klassen (CWE)

  • CWE-347Base

    Improper Verification of Cryptographic Signature

    The product does not verify, or incorrectly verifies, the cryptographic signature for data.

    cwe.mitre.org →

Re-Analyse & Statuswechsel

Chronologie der NVD-Audit-Events für diese CVE — Reanalyses, CVSS-Updates, CPE-Diffs.

  1. CVE Modified2026-09-09 05:17 UTC· 134c704f-9b21-4f2e-91b3-4a467353bcc0
    • SSVC: {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI… → {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…
  2. CVE Modified2026-09-08 15:18 UTC· 134c704f-9b21-4f2e-91b3-4a467353bcc0
    • SSVC: {"id":"CVE-2026-67276","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…
  3. CVE Modified2026-09-07 14:16 UTC· cvd@cert.pl
    • Description: 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 was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable) → 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)
    • Affected: Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67276.json">CVE-2026-67276</a>
    • Reference: https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802
  4. CVE Modified2026-09-05 21:16 UTC· cvd@cert.pl
    • Description: 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 was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable) → 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 was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
  5. New CVE Received2026-09-05 20:17 UTC· cvd@cert.pl
    • Description: 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 was fixed in versions: 6.49.21 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable)
    • CVSS V4.0: AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    • CWE: CWE-347
    • Affected: New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/67xxx/CVE-2026-67276.json">CVE-2026-67276</a>

Quellen & Referenzen

Verknüpfte Empfehlungen

IDCVE-2026-67276