What’s Vulnerable › Vulnerabilities

CVE-2021-31559: S2S TcpToken authentication bypass

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-05-06 · updated 2026-06-17
• Weakness: CWE-288

Description

A crafted request bypasses S2S TCP Token authentication writing arbitrary events to an index in Splunk Enterprise Indexer 8.1 versions before 8.1.5 and 8.2 versions before 8.2.1. The vulnerability impacts Indexers configured to use TCPTokens. It does not impact Universal Forwarders.

Affected products

• Splunk Enterprise: from 8.1.0 before 8.1.5; 8.2.0 — fixed in 8.1.5

How to fix

Upgrade to a fixed version: Splunk Enterprise 8.1.5. Check the vendor advisory for mitigations.

References

• https://www.splunk.com/en_us/product-security/announcements/svd-2022-0503.html
• https://www.splunk.com/en_us/product-security/announcements/svd-2022-0503.html

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