Information disclosure via stale extract32 length
Published Feb 26, 2024 · Updated Oct 25, 2024
Out-of-bounds reads in Vyper before 0.4.0 allow remote attackers to obtain stale EVM memory from affected smart contracts. Extract32.build_IR caches the byte-array pointer and length before evaluating start, but not the contents, so a side effect that changes the array pairs an obsolete length with new data. A deployed contract must pass a start expression that mutates the same array; extract32 then returns dirty bytes instead of the intended value.
Summary
What happened
Out-of-bounds reads in Vyper before 0.4.0 allow remote attackers to obtain stale EVM memory from affected smart contracts. Extract32.build_IR caches the byte-array pointer and length before evaluating start, but not the contents, so a side effect that changes the array pairs an obsolete length with new data. A deployed contract must pass a start expression that mutates the same array; extract32 then returns dirty bytes instead of the intended value.
The record
- CVE
- CVE-2024-24564
- Published
- Feb 26, 2024
- Updated
- Oct 25, 2024
- Vendor
- Vyper
- Product
- Vyper
- Classifications
- CWE-125
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 26, 2024CVE publishedPublication date reported by the CVE source.
- Oct 25, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <0.4.0
- Affected versionversion=< 0.4.0
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
- Upstream extract32 dirty-memory proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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