How severe is CVE-2020-11881?

CVE-2020-11881 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-11881 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-11881?

CVE-2020-11881 primarily affects Mikrotik Routeros. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-11881?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-11881 published?

CVE-2020-11881 was published on 2020-09-14 and last updated on 2026-06-17.

CVE-2020-11881

CVE-2020-11881 is a high-severity vulnerability in Mikrotik Routeros with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-129.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-129
Affected product: Mikrotik Routeros
Published: 2020-09-14
Last modified: 2026-06-17

Description

An array index error in MikroTik RouterOS 6.41.3 through 6.46.5, and 7.x through 7.0 Beta5, allows an unauthenticated remote attacker to crash the SMB server via modified setup-request packets, aka SUP-12964.

Frequently asked questions

What is CVE-2020-11881?: An array index error in MikroTik RouterOS 6.41.3 through 6.46.5, and 7.x through 7.0 Beta5, allows an unauthenticated remote attacker to crash the SMB server via modified setup-request packets, aka SUP-12964.
How severe is CVE-2020-11881?: CVE-2020-11881 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-11881 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-11881?: CVE-2020-11881 primarily affects Mikrotik Routeros. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-11881?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-11881 published?: CVE-2020-11881 was published on 2020-09-14 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*
cpe:2.3:o:mikrotik:routeros:7.0:beta3:*:*:*:*:*:*
cpe:2.3:o:mikrotik:routeros:7.0:beta4:*:*:*:*:*:*
cpe:2.3:o:mikrotik:routeros:7.0:beta5:*:*:*:*:*:*

More vulnerabilities in Mikrotik Routeros

CVE-2017-20149 — Critical (CVSS 9.8): The Mikrotik RouterOS web server allows memory corruption in releases before Stable 6.38.5 and Long-term 6.37.5, aka…
CVE-2022-34960 — Critical (CVSS 9.8): The container package in MikroTik RouterOS 7.4beta4 allows an attacker to create mount points pointing to symbolic…
CVE-2018-7445 — Critical (CVSS 9.8): A buffer overflow was found in the MikroTik RouterOS SMB service when processing NetBIOS session request messages.…
CVE-2023-30799 — Critical (CVSS 9.1): MikroTik RouterOS stable before 6.49.7 and long-term through 6.48.6 are vulnerable to a privilege escalation issue. A…
CVE-2018-14847 — Critical (CVSS 9.1): MikroTik RouterOS through 6.42 allows unauthenticated remote attackers to read arbitrary files and remote authenticated…
CVE-2022-45313 — High (CVSS 8.8): Mikrotik RouterOs before stable v7.5 was discovered to contain an out-of-bounds read in the hotspot process. This…

All CVEs affecting Mikrotik Routeros →

Other CWE-129 (Improper Validation of Array Index) vulnerabilities

CVE-2020-27485 — Critical (CVSS 9.9): Garmin Forerunner 235 before 8.20 is affected by: Array index error. The component is: ConnectIQ TVM. The attack vector…
CVE-2020-27483 — Critical (CVSS 9.9): Garmin Forerunner 235 before 8.20 is affected by: Array index error. The component is: ConnectIQ TVM. The attack vector…
CVE-2026-21413 — Critical (CVSS 9.8): A heap-based buffer overflow vulnerability exists in the lossless_jpeg_load_raw functionality of LibRaw Commit 0b56545…
CVE-2025-27034 — Critical (CVSS 9.8): Memory corruption while selecting the PLMN from SOR failed list.
CVE-2025-3357 — Critical (CVSS 9.8): IBM Tivoli Monitoring 6.3.0.7 through 6.3.0.7 Service Pack 19 could allow a remote attacker to execute arbitrary code…
CVE-2024-45569 — Critical (CVSS 9.8): Memory corruption while parsing the ML IE due to invalid frame content.

Browse all CWE-129 (Improper Validation of Array Index) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

35.130.111.146 (ipv4-addr)
27.110.176.222 (ipv4-addr)
102.64.43.181 (ipv4-addr)