CVE-2021-43839 | Drainage of FeeCollector's Block Transaction Fees

Cronos is a commercial implementation of a blockchain. In Cronos nodes running versions before v0.6.5, it is possible to take transaction fees from Cosmos SDK's FeeCollector for the current block by sending a custom crafted MsgEthereumTx. This problem has been patched in Cronos v0.6.5. There are no tested workarounds. All validator node operators are recommended to upgrade to Cronos v0.6.5 at their earliest possible convenience.

Published: 2021-12-21 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-43839 is rated Moderate Risk (47.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.27%). Review affected assets and schedule 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-2021-43839

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 2025-03-17 0.06% 0.27% +0.21%
2 2023-03-07 0.95% 0.06% -0.89%
3 2022-02-04 — 0.95% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-43839

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N 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:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-43839

GitHub Security Advisory for CVE-2021-43839

GHSA-f854-hpxv-cw9r · Severity: high · Ecosystem: go — Drainage of FeeCollector's Block Transaction Fees in cronos

Affected software / configurations for CVE-2021-43839

Vendor Product Version Raw CPE
crypto cronos < 0.6.5 cpe:2.3:a:crypto:cronos:*:*:*:*:*:*:*:*
crypto ethermint < 0.7.3 cpe:2.3:a:crypto:ethermint:*:*:*:*:*:*:*:*
crypto ethermint >= 0.8.0, <= 0.9.0 cpe:2.3:a:crypto:ethermint:*:*:*:*:*:*:*:*
crypto evmos <= 0.4.2 cpe:2.3:a:crypto:evmos:*:*:*:*:*:*:*:*

References for CVE-2021-43839

cvelogic Threat Intelligence