CVE-2021-20856

lowpriority · track · 22EPSS 0.006 · 49 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.60% (49th) EPSS

CVSS 3.5 · low

Is it mine?

3 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-28

Cross-site scripting vulnerability in ELECOM LAN routers (WRH-733GBK firmware v1.02.9 and prior and WRH-733GWH firmware v1.02.9 and prior) allows a remote authenticated attacker to inject an arbitrary script via unspecified vectors.

cvss

Technical severity, 0–10. One row per scoring source.

5.4

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.5–5.4

v2.03.5lowAV:N/AC:M/Au:S/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 6.8 · impact 2.9

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.3 · impact 2.7

v3.15mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USprimary

affected products (3)

Products and version ranges known to be affected.

ELECOM CO.,LTD. ELECOM LAN routers≤ WRH-733GBK firmware v1.02.9 and prior and WRH-733GWH firmware v1.02.9 and priorenisa_euvdEU
elecom wrh-733gbk firmware≤ 1.02.9nvdUScpe:2.3:o:elecom:wrh-733gbk_firmware:*:*:*:*:*:*:*:*
elecom wrh-733gwh firmware≤ 1.02.9nvdUScpe:2.3:o:elecom:wrh-733gwh_firmware:*:*:*:*:*:*:*:*

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2021-12-01modified 2026-06-17

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+53061 more

references (9)

External citations — patches, advisories, analysis.

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