How severe is CVE-2021-20653?

CVE-2021-20653 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-20653 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20653?

CVE-2021-20653 primarily affects Nec Csdj-b Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20653?

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

When was CVE-2021-20653 published?

CVE-2021-20653 was published on 2021-02-17 and last updated on 2026-06-17.

CVE-2021-20653

CVE-2021-20653 is a medium-severity vulnerability in Nec Csdj-b Firmware with a CVSS 3.x base score of 5.3. 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-276.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-276
Affected product: Nec Csdj-b Firmware
Published: 2021-02-17
Last modified: 2026-06-17

Description

Calsos CSDJ (CSDJ-B 01.08.00 and earlier, CSDJ-H 01.08.00 and earlier, CSDJ-D 01.08.00 and earlier, and CSDJ-A 03.08.00 and earlier) allows remote attackers to bypass access restriction and to obtain unauthorized historical data without access privileges via unspecified vectors.

Frequently asked questions

What is CVE-2021-20653?: Calsos CSDJ (CSDJ-B 01.08.00 and earlier, CSDJ-H 01.08.00 and earlier, CSDJ-D 01.08.00 and earlier, and CSDJ-A 03.08.00 and earlier) allows remote attackers to bypass access restriction and to obtain unauthorized historical data without access privileges via unspecified vectors.
How severe is CVE-2021-20653?: CVE-2021-20653 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-20653 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20653?: CVE-2021-20653 primarily affects Nec Csdj-b Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20653?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-20653 published?: CVE-2021-20653 was published on 2021-02-17 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:nec:csdj-b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:nec:csdj-h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:nec:csdj-d_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:nec:csdj-a_firmware:*:*:*:*:*:*:*:*

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