How severe is CVE-2020-20266?

CVE-2020-20266 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-20266 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-20266?

CVE-2020-20266 affects Mikrotik Routeros. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-20266?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-20266 published?

CVE-2020-20266 was published on 2021-05-19 and last updated on 2026-06-17.

CVE-2020-20266

CVE-2020-20266 is a medium-severity vulnerability in Mikrotik Routeros with a CVSS 3.x base score of 6.5. 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 2% (79th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Mikrotik Routeros
Published: 2021-05-19
Last modified: 2026-06-17

Description

Mikrotik RouterOs before 6.47 (stable tree) suffers from a memory corruption vulnerability in the /nova/bin/dot1x process. An authenticated remote attacker can cause a Denial of Service (NULL pointer dereference).

Frequently asked questions

What is CVE-2020-20266?: Mikrotik RouterOs before 6.47 (stable tree) suffers from a memory corruption vulnerability in the /nova/bin/dot1x process. An authenticated remote attacker can cause a Denial of Service (NULL pointer dereference).
How severe is CVE-2020-20266?: CVE-2020-20266 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-20266 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-20266?: CVE-2020-20266 affects Mikrotik Routeros. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-20266?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-20266 published?: CVE-2020-20266 was published on 2021-05-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:mikrotik:routeros:*:*:*:*:-:*:*:*

More vulnerabilities in Mikrotik Routeros

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CVE-2018-14847 — Critical (CVSS 9.1): MikroTik RouterOS through 6.42 allows unauthenticated remote attackers to read arbitrary files and remote authenticated…
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All CVEs affecting Mikrotik Routeros →

Other CWE-476 (NULL Pointer Dereference) vulnerabilities

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CVE-2020-14500 — Critical (CVSS 10.0): Secomea GateManager all versions prior to 9.2c, An attacker can send a negative value and overwrite arbitrary data.
CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
CVE-2026-46195 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building…
CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
CVE-2026-31436 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: fix possible wrong descriptor…

Browse all CWE-476 (NULL Pointer Dereference) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

35.130.111.98 (ipv4-addr)
27.110.176.222 (ipv4-addr)