Session Token Replay Vulnerability in MikroTik RouterOS WebFig Interface
CVE-2026-89035

9.1CRITICAL

Key Information:

Vendor

Mikrotik

Status
Routeros
Vendor
CVE Published:
21 October 2026

What is CVE-2026-89035?

MikroTik RouterOS versions up to 7.24.5 suffer from a vulnerability allowing attackers to exploit captured session tokens in the WebFig interface. The flaw arises from the makeSessionKey function in libucrypto.so, which generates tokens using fixed salts without considering specific channel or session inputs. Consequently, unauthorized users can replay these tokens to bypass authentication protocols, granting them persistent administrative access until the token store is manually cleared. This issue amplifies the risks identified in a prior vulnerability related to transport-layer weaknesses.

Affected Version(s)

RouterOS 0 <= 7.23.6

RouterOS 7.24.0 <= 7.24.5

References

https://www.vulncheck.com/advisories/mikrotik-routeros-we...
third-party-advisory

CVSS V4

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Valentin Lobstein (Chocapikk)
.