CVE-2023-39363
Each function using a named re-entrancy lock gets a unique lock regardless of the key, allowing cross-function re-entrancy in contracts compiled with the susceptible versions.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.82%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM). In versions 0.2.15, 0.2.16 and 0.3.0, named re-entrancy locks are allocated incorrectly. Each function using a named re-entrancy lock gets a unique lock regardless of the key, allowing cross-function re-entrancy in contracts compiled with the susceptible versions. A specific set of conditions is required to result in misbehavior of affected contracts, specifically: a `.vy` contract compiled with `vyper` versions `0.2.15`, `0.2.16`, or `0.3.0`; a primary function that utilizes the `@nonreentrant` decorator with a specific `key` and does not strictly follow the check-effects-interaction pattern (i.e. contains an external call to an untrusted party before storage updates); and a secondary function that utilizes the same `key` and would be affected by the improper state caused by the primary function. Version 0.3.1 contains a fix for this issue.
- CVSS 4.0
- 9.1 CRITICALCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H/E:A/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.82% probability · 55th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-863
- Affected
- vyperlang/vyper
- Source
- security-advisories@github.com
References
- https://github.com/vyperlang/vyper/pull/2439Patch
- https://github.com/vyperlang/vyper/pull/2514Patch
- https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38Exploit, Patch, Third Party Advisory
- https://hackmd.io/@LlamaRisk/BJzSKHNjnExploit, Third Party Advisory
- https://hackmd.io/@vyperlang/HJUgNMhs2Exploit, Third Party Advisory
- https://github.com/vyperlang/vyper/pull/2439Patch
- https://github.com/vyperlang/vyper/pull/2514Patch
- https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38Exploit, Patch, Third Party Advisory
- https://hackmd.io/@LlamaRisk/BJzSKHNjnExploit, Third Party Advisory
- https://hackmd.io/@vyperlang/HJUgNMhs2Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.