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Plain meaning

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A vulnerability where a program accepts an account in a privileged role (e.g., admin, authority, payer) without verifying that the account actually signed the transaction, allowing any caller to impersonate that authority by simply passing the target pubkey as an instruction account. In native Solana programs, the check requires asserting account.is_signer == true; in Anchor, the Signer<'info> type enforces this automatically. Exploitation lets an attacker bypass all access control gated on authority equality checks, making it one of the most critical and commonly audited vulnerabilities in Solana programs.

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Missing Signer Check (missing-signer-check)
Category: Security
Definition: A vulnerability where a program accepts an account in a privileged role (e.g., admin, authority, payer) without verifying that the account actually signed the transaction, allowing any caller to impersonate that authority by simply passing the target pubkey as an instruction account. In native Solana programs, the check requires asserting account.is_signer == true; in Anchor, the Signer<'info> type enforces this automatically. Exploitation lets an attacker bypass all access control gated on authority equality checks, making it one of the most critical and commonly audited vulnerabilities in Solana programs.
Related: Signer, Authority

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Signer

An account that has provided a valid Ed25519 signature in the current transaction. The runtime enforces the is_signer flag on instruction account metas—if an instruction declares an account as a signer, the transaction must include its signature. Missing signer checks are a common vulnerability in Solana programs.

Keypair Transaction

Open term

Branch

Authority

A pubkey with administrative privileges over a resource—such as the mint authority (can mint tokens), freeze authority (can freeze accounts), upgrade authority (can upgrade a program), or the signer authorized to perform operations on a PDA-controlled account. Authority is a convention, not a runtime concept.

Owner (Account)Multisig

Open term

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Programming Model

Signer

An account that has provided a valid Ed25519 signature in the current transaction. The runtime enforces the is_signer flag on instruction account metas—if an instruction declares an account as a signer, the transaction must include its signature. Missing signer checks are a common vulnerability in Solana programs.

Open term

Programming Model

Authority

A pubkey with administrative privileges over a resource—such as the mint authority (can mint tokens), freeze authority (can freeze accounts), upgrade authority (can upgrade a program), or the signer authorized to perform operations on a PDA-controlled account. Authority is a convention, not a runtime concept.

Open term

Security

Neodyme

Security research firm specializing in Solana program auditing and vulnerability research. Published influential work on common Solana vulnerabilities and maintains educational resources on program security patterns. Based in Germany.

Open term

Security

Missing Owner Check

A vulnerability where a program deserializes and trusts account data without first confirming that the account is owned by the expected program, allowing an attacker to substitute a maliciously crafted account owned by a different program whose byte layout happens to satisfy the deserialization. On Solana, every account stores a 32-byte owner field set to the program that created it; native programs must assert account.owner == &expected_program_id, while Anchor's Account<'info, T> wrapper performs this check automatically. Failure to validate ownership can lead to complete auth bypass if an attacker can construct a fake account whose data parses into a struct with elevated privileges.

Open term

Commonly confused with

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Securitymissing-owner-check

Missing Owner Check

A vulnerability where a program deserializes and trusts account data without first confirming that the account is owned by the expected program, allowing an attacker to substitute a maliciously crafted account owned by a different program whose byte layout happens to satisfy the deserialization. On Solana, every account stores a 32-byte owner field set to the program that created it; native programs must assert account.owner == &expected_program_id, while Anchor's Account<'info, T> wrapper performs this check automatically. Failure to validate ownership can lead to complete auth bypass if an attacker can construct a fake account whose data parses into a struct with elevated privileges.

Open term

Related terms

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Programming Modelsigner

Signer

An account that has provided a valid Ed25519 signature in the current transaction. The runtime enforces the is_signer flag on instruction account metas—if an instruction declares an account as a signer, the transaction must include its signature. Missing signer checks are a common vulnerability in Solana programs.

Open term

Programming Modelauthority

Authority

A pubkey with administrative privileges over a resource—such as the mint authority (can mint tokens), freeze authority (can freeze accounts), upgrade authority (can upgrade a program), or the signer authorized to perform operations on a PDA-controlled account. Authority is a convention, not a runtime concept.

Open term

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Security

Missing Owner Check

A vulnerability where a program deserializes and trusts account data without first confirming that the account is owned by the expected program, allowing an attacker to substitute a maliciously crafted account owned by a different program whose byte layout happens to satisfy the deserialization. On Solana, every account stores a 32-byte owner field set to the program that created it; native programs must assert account.owner == &expected_program_id, while Anchor's Account<'info, T> wrapper performs this check automatically. Failure to validate ownership can lead to complete auth bypass if an attacker can construct a fake account whose data parses into a struct with elevated privileges.

Open term

Security

Arbitrary CPI

A vulnerability where a program accepts an arbitrary program account from the caller and invokes it via Cross-Program Invocation (CPI) without verifying it matches a known, trusted program ID, effectively letting an attacker substitute a malicious program that executes under the victim program's authority or manipulates accounts the victim program passes to it. A common pattern is accepting a token_program account without checking it equals spl_token::ID, so the attacker passes a lookalike program that records or drains account data. Prevention requires hard-coding or explicitly checking the program ID before every CPI call.

Open term

Security

PDA Substitution Attack

A vulnerability where a program derives a PDA internally but accepts an externally supplied account as that PDA without re-deriving and comparing the address, allowing an attacker to pass a different PDA (derived from attacker-controlled seeds) that the program will treat as legitimate. Because PDAs are deterministic, the only way to guarantee account identity is to call Pubkey::find_program_address (or equivalent) with the expected seeds inside the program and assert the result equals the supplied key. Anchor's seeds and bump constraints on the Account type automate this re-derivation and equality check.

Open term

Security

Account Reloading Attack

A vulnerability in Anchor programs where a program reads an account's data before making a CPI call, the CPI modifies that account's lamports or data, but the program continues using the stale pre-CPI snapshot instead of reloading the account from the runtime. In Anchor, after a CPI the account reference still holds the pre-call data unless account.reload() is explicitly called, meaning balance checks, state assertions, or further computation can operate on incorrect values. Attackers can exploit this to pass checks using an initial account state that the CPI subsequently invalidates.

Open term