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medium Low-Level / Assembly No SWC entry CWE-436

ABI Encoding Collision / Selector Clash

SAFE-0088 Low-Level / Assembly Checked automatically by the scanner
1

What goes wrong

In transparent proxies or multiplexed dispatchers, an implementation function selector can collide with an admin/proxy selector, so a user call is silently routed to the wrong function.

2

How to fix it

the pattern that is safe
// Use OZ TransparentUpgradeableProxy: admin and user call spaces are separated
◆
Avoid selector clashes; use transparent proxy semantics.
3

Where this has happened

Largest recorded losses in the same failure class — related, not the same bug:

$69.3M · 2023 Curve Finance · Vyper compiler Compiler / toolchain + Reentrancy · 2023
4

Related vulnerabilities in Low-Level / Assembly

SAFE-0117delegatecall to User-Controlled Target critical · Low-Level / Assembly SAFE-0032Memory Corruption in Assembly high · Low-Level / Assembly SAFE-0236CREATE2 Address Reuse After selfdestruct (Metamorphic) high · Low-Level / Assembly SAFE-0302delegatecall Inside a Loop high · Low-Level / Assembly SAFE-0031Dirty Higher-Order Bits / Unsafe Assembly Math medium · Low-Level / Assembly SAFE-0235Inline Assembly Not Marked memory-safe low · Low-Level / Assembly SAFE-0303Inline Assembly return/revert Bypasses Solidity low · Low-Level / Assembly
← PreviousDust Accumulation / Rounding Residue Lockup
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