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Fencer Vulns
high 7.5

CVE-2021-43839 json

Drainage of FeeCollector's Block Transaction Fees

published 2021-12-21 4 y ago modified 2026-07-08 4 mo ago also GHSA-f854-hpxv-cw9r , EUVD-2022-0577

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/crypto-org-chain/cronos 0.6.5
  • go github.com/tharsis/ethermint 0.7.3, 0.10.0
  • crypto cronos 0.6.5
  • crypto ethermint 0.7.3

Exploit prediction

1.36% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/crypto-org-chain/cronos
<0.6.5
0.6.5
go github.com/tharsis/ethermint
>=0.8.0, <0.10.0
<0.7.3
0.10.0
0.7.3
go github.com/tharsis/evmos
<=0.4.2
 no fix listed

Affected products

  • crypto-org-chain cronos

Classification

Weakness
  • CWE-670 Always-Incorrect Control Flow Implementation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.