GHSA-429q-fhh4-r6hj

Impact

Any uses of InterfaceAccount allows another unexpected account type to be passed, after https://github.com/solana-foundation/anchor/pull/3837 disabled discriminator checking for this type.

The bug was originally reported and fixed in https://github.com/solana-foundation/anchor/pull/4139, see that PR for more details.

Patches

https://github.com/solana-foundation/anchor/pull/4139 patched the issue and was released in 1.0.0-rc.2. Users should upgrade to the latest released version of Anchor 1.0.

References

Bug landed in: https://github.com/solana-foundation/anchor/pull/3837 Bug fixed in: https://github.com/solana-foundation/anchor/pull/4139

Impact

Any uses of InterfaceAccount allows another unexpected account type to be passed, after https://github.com/solana-foundation/anchor/pull/3837 disabled discriminator checking for this type.

The bug was originally reported and fixed in https://github.com/solana-foundation/anchor/pull/4139, see that PR for more details.

Patches

https://github.com/solana-foundation/anchor/pull/4139 patched the issue and was released in 1.0.0-rc.2. Users should upgrade to the latest released version of Anchor 1.0.

References

Bug landed in: https://github.com/solana-foundation/anchor/pull/3837 Bug fixed in: https://github.com/solana-foundation/anchor/pull/4139

Affected versions of anchor-lang allowed InterfaceAccount to accept accounts with an unexpected Anchor discriminator. A change to InterfaceAccount caused checked deserialization to be bypassed for this account wrapper, so validation proved only that the account owner matched one of the accepted interface owners. It did not prove that the account data belonged to the expected account type.

Programs using InterfaceAccount rely on Anchor to enforce both owner and account-type validation before the handler runs. With discriminator checking disabled, an attacker could pass another account type owned by an accepted program and have it deserialized through the expected interface wrapper. This could bypass account-type assumptions made by the program and lead to incorrect authorization or state handling.

The issue was fixed in anchor-lang 1.0.0-rc.2 by restoring checked deserialization for InterfaceAccount::try_from, while keeping explicitly unchecked behavior available only through the unchecked API. Users should upgrade to anchor-lang 1.0.0-rc.2 or later.