Cyber Resilience

CVE-2021-31559

High

Published: 06 May 2022

Published
06 May 2022
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0020 41.8th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-31559 is a high-severity Authentication Bypass Using an Alternate Path or Channel (CWE-288) vulnerability in Splunk Splunk. Its CVSS base score is 7.5 (High).

Operationally, ranked at the 41.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

Forwarders.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

splunk
splunk
8.2.0 · 8.1.0 — 8.1.5

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-288

Authorizing remote access reduces the ability to bypass authentication via unauthorized alternate remote channels.

addresses: CWE-288

Users can identify logons via alternate paths or channels by reviewing the previous logon time.

addresses: CWE-288

Adaptive requirements can apply across access paths, reducing the ability to bypass authentication via alternate channels or paths.

addresses: CWE-288

Centralized IdPs close alternate authentication paths that enable bypass.

addresses: CWE-288

Enforces authentication for non-organizational users, making it harder to bypass via alternate paths or channels.

addresses: CWE-288

Requires authentication to occur exclusively over the isolated trusted path, directly preventing bypass via alternate or untrusted channels.

References