Glossary OS

Plain meaning

Start with the shortest useful explanation before going deeper.

A class of numerical vulnerability where integer division discards fractional remainders, causing systematic under-accounting of fees, interest, or token amounts that an attacker can exploit through repeated small transactions to drain protocol funds or receive more than entitled. Because Solana programs use integer arithmetic exclusively (no native floating point in on-chain code), division operations like amount / price always truncate toward zero, and protocols must decide whether to round in favor of the protocol (ceiling division for fees collected, floor division for tokens distributed) using formulas such as (numerator + denominator - 1) / denominator. Precision errors can also compound across fixed-point representations, so high-precision intermediate scaling (e.g., multiplying by 10^9 before dividing) is a common mitigation.

Mental model

Use the quick analogy first so the term is easier to reason about when you meet it in code, docs, or prompts.

Think of it as a building block that connects one definition to the larger Solana system around it.

Technical context

Place the term inside its Solana layer so the definition is easier to reason about.

Failure modes, audits, attack surfaces, and safe design patterns.

Why builders care

Turn the term from vocabulary into something operational for product and engineering work.

This term unlocks adjacent concepts quickly, so it works best when you treat it as a junction instead of an isolated definition.

AI handoff

Use this compact block when you want to give an agent or assistant grounded context without dumping the entire page.

Precision Loss / Rounding Errors (precision-loss)
Category: Security
Definition: A class of numerical vulnerability where integer division discards fractional remainders, causing systematic under-accounting of fees, interest, or token amounts that an attacker can exploit through repeated small transactions to drain protocol funds or receive more than entitled. Because Solana programs use integer arithmetic exclusively (no native floating point in on-chain code), division operations like amount / price always truncate toward zero, and protocols must decide whether to round in favor of the protocol (ceiling division for fees collected, floor division for tokens distributed) using formulas such as (numerator + denominator - 1) / denominator. Precision errors can also compound across fixed-point representations, so high-precision intermediate scaling (e.g., multiplying by 10^9 before dividing) is a common mitigation.
Related: Integer Overflow / Underflow

Glossary Copilot

Ask grounded Solana questions without leaving the glossary.

Use glossary context, relationships, mental models, and builder paths to get structured answers instead of generic chat output.

Open full Copilot workspace

Question

Explain this code

Optional: paste Anchor, Solana, or Rust code so the Copilot can map primitives back to glossary terms.

Ask a glossary-grounded question

The Copilot will answer using the current term, related concepts, mental models, and the surrounding glossary graph.

Concept graph

See the term as part of a network, not a dead-end definition.

These branches show which concepts this term touches directly and what sits one layer beyond them.

Branch

Integer Overflow / Underflow

A class of arithmetic vulnerabilities where an integer computation produces a result outside the bounds of its fixed-width type, wrapping around silently in Rust's release builds (since Rust panics on overflow only in debug mode), yielding an incorrect value that can corrupt token balances, borrow limits, or access control counters. For example, subtracting a larger u64 from a smaller one wraps to near u64::MAX (~1.8 × 10^19), which could be interpreted as an enormous balance. Solana programs must use Rust's checked_add, checked_sub, checked_mul, and checked_div methods (or the saturating_* / wrapping_* variants with deliberate intent) on all financial arithmetic to eliminate this class of bugs.

Checked Math

Open term

Next concepts to explore

Keep the learning chain moving instead of stopping at one definition.

These are the next concepts worth opening if you want this term to make more sense inside a real Solana workflow.

Security

Integer Overflow / Underflow

A class of arithmetic vulnerabilities where an integer computation produces a result outside the bounds of its fixed-width type, wrapping around silently in Rust's release builds (since Rust panics on overflow only in debug mode), yielding an incorrect value that can corrupt token balances, borrow limits, or access control counters. For example, subtracting a larger u64 from a smaller one wraps to near u64::MAX (~1.8 × 10^19), which could be interpreted as an enormous balance. Solana programs must use Rust's checked_add, checked_sub, checked_mul, and checked_div methods (or the saturating_* / wrapping_* variants with deliberate intent) on all financial arithmetic to eliminate this class of bugs.

Open term

Security

Privilege Escalation

A class of vulnerabilities where an attacker gains a higher level of authority than legitimately granted — for example, forging admin access, hijacking a program's upgrade authority, or obtaining a PDA signer without possessing the seeds that should gate it. On Solana, common vectors include missing signer checks (an account is treated as an authority without asserting is_signer), misconfigured multisig authority accounts, and upgrade authority mismanagement (leaving a program upgradeable by a hot wallet instead of a governance multisig or burning the upgrade authority entirely). Programs should enforce the principle of least privilege by using immutable upgrade authorities or time-locked governance for high-value programs.

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

Missing Signer Check

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.

Open term

Related terms

Follow the concepts that give this term its actual context.

Glossary entries become useful when they are connected. These links are the shortest path to adjacent ideas.

Securityinteger-overflow

Integer Overflow / Underflow

A class of arithmetic vulnerabilities where an integer computation produces a result outside the bounds of its fixed-width type, wrapping around silently in Rust's release builds (since Rust panics on overflow only in debug mode), yielding an incorrect value that can corrupt token balances, borrow limits, or access control counters. For example, subtracting a larger u64 from a smaller one wraps to near u64::MAX (~1.8 × 10^19), which could be interpreted as an enormous balance. Solana programs must use Rust's checked_add, checked_sub, checked_mul, and checked_div methods (or the saturating_* / wrapping_* variants with deliberate intent) on all financial arithmetic to eliminate this class of bugs.

Open term

Stay in the same layer and keep building context.

These entries live beside the current term and help the page feel like part of a larger knowledge graph instead of a dead end.

Security

Missing Signer Check

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.

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

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