CVE-2026-89028

MikroTik RouterOS < 7.24 Heap Corruption via SMB1 SessionSetupAndX

At a glance

Severity: HIGH 8.2
EPSS: EPSS 0.58 % · percentile 48 (2026-10-27)
State: PUBLISHED
Published: 2026-09-16
Updated: 2026-10-01
Assigner: VulnCheck
NVD status: Awaiting Analysis

Description

MikroTik RouterOS before 7.24 contains a heap memory corruption vulnerability in the userspace SMB daemon that allows remote attackers to corrupt adjacent heap memory by supplying a crafted uniPwdLen value in the SMB1 SessionSetupAndX handler. An attacker can send a malformed SMB1 request with a uniPwdLen field that triggers an integer underflow, causing the resulting value to be used as the copy length in a memory copy operation into a smaller heap buffer, corrupting adjacent heap memory.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	HIGH 8.2	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	VulnCheck
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	VulnCheck
CVSS 4.0	HIGH 8.2	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/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	NVD · disclosure@vulncheck.com (Secondary)
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	NVD · disclosure@vulncheck.com (Secondary)

Weaknesses (CWE)

European references

ENISA EUVD · EUVD-2026-80702
GCVE · GCVE-0-2026-89028

Affected products

Product	Versions
MikroTik · RouterOS	affected 0 ≤ 6.49.18 ; affected 7.0.0 ≤ 7.11.2 ; unaffected 7.24.0

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD