What is the CVSS score of CVE-2025-21607?

CVE-2025-21607 has a CVSS 4.0 base score of 2.3 (Low). CVSS vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. EPSS exploitation probability: 0.4%.

Is there a public PoC exploit available for CVE-2025-21607?

Yes, a public proof-of-concept exploit is available for CVE-2025-21607. Prioritise patching immediately. EPSS: 0.4%.

How to fix or mitigate CVE-2025-21607?

During next maintenance window: Apply vendor patches when convenient. Monitor vendor channels for updates.

Vyper CVE-2025-21607

LOW

Always-Incorrect Control Flow Implementation (CWE-670)

2025-01-14 security-advisories@github.com

Information Disclosure Vyper Vyperlang

2.3

CVSS 4.0 · GitHub Advisory

View

Vulnerability Assessment

Weakness	CWE CWE-670 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Always-incorrect control flow
Impact	CVSS score of 2.3 (LOW). Attack characteristics: network attack vector, high complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.39%.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the low-severity affected system.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).

Patch available 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Vyper is a Pythonic Smart Contract Language for the EVM. Rated low severity (CVSS 2.3), this vulnerability is remotely exploitable. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affected Packages

pypi vyper fix: 0.4.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in pypi

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-670. Vyper is a Pythonic Smart Contract Language for the EVM. When the Vyper Compiler uses the precompiles EcRecover (0x1) and Identity (0x4), the success flag of the call is not checked. As a consequence an attacker can provide a specific amount of gas to make these calls fail but let the overall execution continue. Then the execution result can be incorrect. Based on EVM's rules, after the failed precompile the remaining code has only 1/64 of the pre-call-gas left (as 63/64 were forwarded and spent). Hence, only fairly simple executions can follow the failed precompile calls. Therefore, we found no significantly impacted real-world contracts. None the less an advisory has been made out of an abundance of caution. This issue is fixed in 0.4.1. Affected products include: Vyperlang Vyper.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 2.3 LOW

CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

High

Attack Requirements

Present

Privileges Required

Low

User Interaction

None

Vulnerable system: Confidentiality

None

Vulnerable system: Integrity

Low

Vulnerable system: Availability

None

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

PoC Detected

Apr 24, 2025 - 15:15 vuln.today

Public exploit code

CVE Published

Jan 14, 2025 - 18:16 nvd

LOW 2.3

DescriptionGitHub Advisory

Vyper is a Pythonic Smart Contract Language for the EVM. When the Vyper Compiler uses the precompiles EcRecover (0x1) and Identity (0x4), the success flag of the call is not checked. As a consequence an attacker can provide a specific amount of gas to make these calls fail but let the overall execution continue. Then the execution result can be incorrect. Based on EVM's rules, after the failed precompile the remaining code has only 1/64 of the pre-call-gas left (as 63/64 were forwarded and spent). Hence, only fairly simple executions can follow the failed precompile calls. Therefore, we found no significantly impacted real-world contracts. None the less an advisory has been made out of an abundance of caution. This issue is fixed in 0.4.1.

Executive ViewAI

Why It Matters

CVE-2025-21607 is a low-severity vulnerability in Vyper (CVSS 2.3). The limited severity suggests constrained impact, typically requiring specific conditions or local access for exploitation. Apply vendor updates when available as part of routine maintenance.

Business Impact: Low

Compensating Controls

Apply vendor patch during routine maintenance. Standard security controls provide adequate interim protection.

Threat Intelligence Overview

EPSS Score

0.4%

Top 40% exploitable

Exploit

POC

Public exploit code exists

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity LOW

CISA KEV No

Public POC Yes

EPSS 0.4%

Patch available Yes

Active threat No

Deciding rule

LOW severity (CVSS 0.1-3.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact

Low

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +12

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.