CVE-2021-41272
Smart contracts that ask for shifts between approximately 2 billion and 4 billion bits (nonsensical but valid values for the operation) will fail to execute and hence fail to validate.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.42%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Besu is an Ethereum client written in Java. Starting in version 21.10.0, changes in the implementation of the SHL, SHR, and SAR operations resulted in the introduction of a signed type coercion error in values that represent negative values for 32 bit signed integers. Smart contracts that ask for shifts between approximately 2 billion and 4 billion bits (nonsensical but valid values for the operation) will fail to execute and hence fail to validate. In networks where vulnerable versions are mining with other clients or non-vulnerable versions this will result in a fork and the relevant transactions will not be included in the fork. In networks where vulnerable versions are not mining (such as Rinkeby) no fork will result and the validator nodes will stop accepting blocks. In networks where only vulnerable versions are mining the relevant transaction will not be included in any blocks. When the network adds a non-vulnerable version the network will act as in the first case. Besu 21.10.2 contains a patch for this issue. Besu 21.7.4 is not vulnerable and clients can roll back to that version. There is a workaround available: Once a transaction with the relevant shift operations is included in the canonical chain, the only remediation is to make sure all nodes are on non-vulnerable versions.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.42% probability · 71th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-681
- Affected
- linuxfoundation/besu
- Source
- security-advisories@github.com
References
- https://github.com/hyperledger/besu/commit/4170524ac3b45185704fcfbdeeb71b0b05dfa0a1Patch, Third Party Advisory
- https://github.com/hyperledger/besu/pull/3039Issue Tracking, Patch, Third Party Advisory
- https://github.com/hyperledger/besu/security/advisories/GHSA-7pg2-p5vj-xp5hPatch, Third Party Advisory
- https://github.com/hyperledger/besu/commit/4170524ac3b45185704fcfbdeeb71b0b05dfa0a1Patch, Third Party Advisory
- https://github.com/hyperledger/besu/pull/3039Issue Tracking, Patch, Third Party Advisory
- https://github.com/hyperledger/besu/security/advisories/GHSA-7pg2-p5vj-xp5hPatch, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.