IP Address Misconfiguration Vulnerability in Slack Nebula
CVE-2025-62820

4.9MEDIUM

Key Information:

Vendor

Slack

Status
Nebula
Vendor
CVE Published:
23 October 2025

What is CVE-2025-62820?

Slack Nebula versions before 1.9.7 contain a significant vulnerability where the handling of Classless Inter-Domain Routing (CIDR) configurations is flawed. This issue allows the system to incorrectly accept arbitrary source IP addresses within the Nebula network. Such misconfigurations can lead to unauthorized access and disrupt network integrity, necessitating immediate attention from users to upgrade to the latest version to mitigate potential attacks.

Affected Version(s)

Nebula 0 < 1.9.7

References

https://github.com/slackhq/nebula/pull/1493
https://github.com/slackhq/nebula/pull/1494

CVSS V3.1

Score:
4.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2025-62820 : IP Address Misconfiguration Vulnerability in Slack Nebula