Out-of-bounds write through stale DynArray target
Published Feb 21, 2025 · Updated Feb 22, 2025
Out-of-bounds write in Vyper before 0.4.1 allows attackers to corrupt a compiled contract's DynArray state through crafted AugAssign code. The compiler caches the indexed target before evaluating a right-hand expression that shrinks the array, then writes through that stale location without repeating the bounds check. Reachability requires a compiled contract containing this specific target-and-RHS pattern; the write remains within the array object's allocated storage.
Summary
What happened
Out-of-bounds write in Vyper before 0.4.1 allows attackers to corrupt a compiled contract's DynArray state through crafted AugAssign code. The compiler caches the indexed target before evaluating a right-hand expression that shrinks the array, then writes through that stale location without repeating the bounds check. Reachability requires a compiled contract containing this specific target-and-RHS pattern; the write remains within the array object's allocated storage.
The record
- CVE
- CVE-2025-27105
- Published
- Feb 21, 2025
- Updated
- Feb 22, 2025
- Vendor
- Vyper
- Product
- Vyper
- Classifications
- CWE-787
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- Feb 21, 2025CVE publishedPublication date reported by the CVE source.
- Feb 22, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.4.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- DynArray AugAssign proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo