CVE-2021-47821
Published: 16 January 2026
Summary
CVE-2021-47821 is a medium-severity Improper Validation of Specified Quantity in Input (CWE-1284) vulnerability in Raimersoft (inferred from references). Its CVSS base score is 4.6 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 6.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SC-5 (Denial-of-service Protection).
Deeper analysis
CVE-2021-47821 is a denial of service vulnerability in RarmaRadio version 2.72.8. The flaw enables attackers to crash the application by overflowing network configuration fields with large character buffers, such as a 100,000-character buffer pasted into multiple network settings fields, resulting in application instability and potential crash. It is linked to CWE-1284 and carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).
Remote attackers require no privileges and no user interaction to exploit the vulnerability over the network with low complexity. Exploitation causes a denial of service by triggering application instability and crash.
Advisories and related resources include the vendor site at http://www.raimersoft.com/, a proof-of-concept exploit documented at https://www.exploit-db.com/exploits/49906, and a VulnCheck advisory at https://www.vulncheck.com/advisories/rarmaradio-denial-of-service. These references provide further details on the issue, though specific patch or mitigation guidance is not detailed in the available information.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2891
Vulnerability details
RarmaRadio 2.72.8 contains a denial of service vulnerability that allows attackers to crash the application by overflowing network configuration fields with large character buffers. Attackers can generate a 100,000 character buffer and paste it into multiple network settings fields to…
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trigger application instability and potential crash.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Buffer overflow input in network config fields directly enables application crash via exploitation, mapping to Endpoint DoS via Application or System Exploitation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces validation of input length and format on network configuration fields, blocking the oversized buffers that trigger the crash in CVE-2021-47821.
Provides mechanisms to limit resource exhaustion from malformed inputs, mitigating the application-level DoS that results from overflowing the network settings fields.
Applies memory protections that can contain or prevent exploitation of the buffer overflow condition described in the CVE.