Success of Certain Precompile Calls not Checked in Vyper
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 0.4.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: partial
Summary
Vyper is a Pythonic Smart Contract Language for the EVM. When the Vyper Compiler uses the precompiles EcRecover (0x1) and Identity (0x4), the success flag of the call is not checked. As a consequence an attacker can provide a specific amount of gas to make these calls fail but let the overall execution continue. Then the execution result can be incorrect. Based on EVM's rules, after the failed precompile the remaining code has only 1/64 of the pre-call-gas left (as 63/64 were forwarded and spent). Hence, only fairly simple executions can follow the failed precompile calls. Therefore, we found no significantly impacted real-world contracts. None the less an advisory has been made out of an abundance of caution. This issue is fixed in 0.4.1.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- vyperlang vyper
fixed in 0.4.1
- vyperPyPI
fixed in 0.4.1
- vyperPyPI
All versions