The Open Web Application Security Project (OWASP) has published the Smart Contract Top 10: 2026, a forward-looking standard awareness document designed to arm Web3 developers, security auditors, and protocol owners with actionable intelligence on the most critical vulnerabilities affecting smart contracts today.
Released as a sub-project of the broader OWASP Smart Contract Security (OWASP SCS) initiative, this edition draws on security incidents and survey data collected throughout 2025, using those empirical findings to project which risks will carry the most impact in the near term.
The 2026 ranking reflects a maturing threat landscape where attackers are no longer relying on simple code bugs alone, but are increasingly chaining vulnerabilities together, combining flash loans with oracle manipulation, or exploiting weak upgrade governance, to maximize financial damage.
With over $2.2 billion lost to crypto hacks in recent years, the urgency of a structured vulnerability framework for the blockchain ecosystem has never been greater.
OWASP Smart Contract Top 10 2026 Vulnerability Rankings
The table below summarizes all ten ranked categories, each linked to its full OWASP specification:
| Rank | Vulnerability | Description |
|---|---|---|
| SC01:2026 | Access Control Vulnerabilities | Flaws that allow unauthorized users or roles to invoke privileged functions or modify critical state, often leading to full protocol compromise. |
| SC02:2026 | Business Logic Vulnerabilities | Design-level flaws in lending, AMM, reward, or governance logic that break economic or functional rules, enabling value extraction even when low-level checks appear correct. |
| SC03:2026 | Price Oracle Manipulation | Weak oracles and unsafe price integrations that let attackers skew reference prices, enabling under-collateralized borrowing and mispriced swaps. |
| SC04:2026 | Flash Loan–Facilitated Attacks | Attacks using large, uncollateralized flash loans to amplify small logic, pricing, or arithmetic bugs into large drains within a single transaction. |
| SC05:2026 | Lack of Input Validation | Missing or weak validation of user, admin, or cross-chain inputs that allows unsafe parameters to reach core logic, corrupting state or enabling fund loss. |
| SC06:2026 | Unchecked External Calls | Unsafe interactions with external contracts where failures, reverts, or callbacks are not safely handled, often enabling reentrancy or inconsistent state. |
| SC07:2026 | Arithmetic Errors | Subtle bugs in integer math, scaling, and rounding — especially in share, interest, and AMM calculations — that can siphon value when paired with flash loans. |
| SC08:2026 | Reentrancy Attacks | External calls that re-enter vulnerable functions before state is fully updated, allowing repeated withdrawals or state changes from outdated contract views. |
| SC09:2026 | Integer Overflow and Underflow | Dangerous arithmetic on code paths without robust overflow checks, leading to wrapped values, broken invariants, and potential liquidity drains. |
| SC10:2026 | Proxy & Upgradeability Vulnerabilities | Misconfigured or weakly governed proxy, initialization, and upgrade mechanisms that let attackers seize control of implementations or reinitialize critical state. |
Notable Shifts from 2025
Compared to the 2025 edition, the 2026 list introduces significant structural changes. Business Logic Vulnerabilities have been elevated to second place, reflecting growing recognition that protocol-level design flaws, not just low-level code bugs, are among the most costly attack surfaces in DeFi.
Proxy & Upgradeability Vulnerabilities (SC10) is an entirely new addition for 2026, signaling that insecure upgrade patterns and weak governance over contract upgrades have become a prominent emerging risk.
Meanwhile, previously ranked categories such as Insecure Randomness and Denial-of-Service attacks have been displaced, reflecting the industry’s evolving attack priorities, as captured in 2025 breach data.
The OWASP Smart Contract Top 10: 2026 is intended to be used alongside complementary OWASP SCS resources, including the OWASP SC Weakness Enumeration (SCWE), the OWASP SCS Checklist, and the OWASP Top 15: Web3 Attack Vectors, together forming a comprehensive framework for secure smart contract development, audit, and compliance.
Follow us on Google News, LinkedIn, and X for daily cybersecurity updates. Contact us to feature your stories.
