CVE-2021-35977

An issue was discovered in Digi RealPort for Windows through 4.8.488.0. A buffer overflow exists in the handling of ADDP discovery response messages. This could result in arbitrary code execution.

Published: 2021-10-08 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-35977 is rated High Risk (66.5/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.03%). High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-35977

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-02 0.68% 1.03% +0.35%
2 2025-11-21 1.03% 0.68% -0.35%
3 2025-11-18 — 1.03% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-35977

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2021-35977

Affected software / configurations for CVE-2021-35977

Vendor Product Version Raw CPE
digi realport <= 1.9-40 cpe:2.3:a:digi:realport:*:*:*:*:*:linux:*:*
digi realport <= 4.8.488.0 cpe:2.3:a:digi:realport:*:*:*:*:*:windows:*:*
digi connectport_ts_8\/16_firmware — cpe:2.3:o:digi:connectport_ts_8\/16_firmware:*:*:*:*:*:*:*:*
digi connectport_lts_8\/16\/32_firmware — cpe:2.3:o:digi:connectport_lts_8\/16\/32_firmware:*:*:*:*:*:*:*:*
digi passport_integrated_console_server_firmware — cpe:2.3:o:digi:passport_integrated_console_server_firmware:*:*:*:*:*:*:*:*
digi cm_firmware — cpe:2.3:o:digi:cm_firmware:*:*:*:*:*:*:*:*
digi portserver_ts_firmware — cpe:2.3:o:digi:portserver_ts_firmware:*:*:*:*:*:*:*:*
digi portserver_ts_mei_firmware — cpe:2.3:o:digi:portserver_ts_mei_firmware:*:*:*:*:*:*:*:*
digi portserver_ts_mei_hardened_firmware — cpe:2.3:o:digi:portserver_ts_mei_hardened_firmware:*:*:*:*:*:*:*:*
digi portserver_ts_m_mei_firmware — cpe:2.3:o:digi:portserver_ts_m_mei_firmware:*:*:*:*:*:*:*:*
digi 6350-sr_firmware — cpe:2.3:o:digi:6350-sr_firmware:*:*:*:*:*:*:*:*
digi portserver_ts_p_mei_firmware — cpe:2.3:o:digi:portserver_ts_p_mei_firmware:*:*:*:*:*:*:*:*
digi transport_wr11_xt_firmware — cpe:2.3:o:digi:transport_wr11_xt_firmware:*:*:*:*:*:*:*:*
digi one_iap_family_firmware — cpe:2.3:o:digi:one_iap_family_firmware:*:*:*:*:*:*:*:*
digi one_ia_firmware — cpe:2.3:o:digi:one_ia_firmware:*:*:*:*:*:*:*:*
digi wr31_firmware — cpe:2.3:o:digi:wr31_firmware:*:*:*:*:*:*:*:*
digi wr44_r_firmware — cpe:2.3:o:digi:wr44_r_firmware:*:*:*:*:*:*:*:*
digi connect_es_firmware — cpe:2.3:o:digi:connect_es_firmware:*:*:*:*:*:*:*:*
digi wr21_firmware — cpe:2.3:o:digi:wr21_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-35977

cvelogic Threat Intelligence