GMS-2021-16: Storage corruption due to variables overwritten by re-entrancy locks

August 5, 2021

Background

When attempting to use the v0.2.14 release, @pandadefi discovered an issue using the @nonreentrant decorator.

Impact

Reentrancy protection storage slots get allocated to the same slots as storage variables, leading to the corruption of storage variables when using the @nonreentrant decorator.

Patches

This issue was fixed in v0.2.15 in #2391, #2379

Workarounds

Don’t use the @nonreentrant decorator in these versions.

References

github.com/advisories/GHSA-7f92-rr6w-cq64
github.com/vyperlang/vyper/pull/2379
github.com/vyperlang/vyper/pull/2391
github.com/vyperlang/vyper/security/advisories/GHSA-7f92-rr6w-cq64

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