RUSTSEC-2026-0146: `InterfaceAccount` allows account substitution between unexpected types

What to do

1. See which version you have: cargo tree -i anchor-lang (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p anchor-lang. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example anchor-lang = "1.0.0-rc.2") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

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.

References

• Package: crates.io/crates/anchor-lang
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0146.html
• Web: github.com/solana-foundation/anchor/pull/3837
• Web: github.com/otter-sec/anchor/pull/3837
• Web: github.com/otter-sec/anchor/pull/4139
• Web: github.com/otter-sec/anchor/commit/26ef36968a62e28a1f028e7adae4806af30c747d

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for anchor-lang

• Vulnerability HighRUSTSEC-2026-0144 · 2026-05-07`Program<System>` accepts arbitrary executable programs

Full security history of anchor-lang