Is CVE-2021-31559 in the CISA KEV catalog?

No. CVE-2021-31559 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-31559?

CVE-2021-31559 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-31559?

CVE-2021-31559 has an EPSS score of 0.83% (53th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-31559?

Upgrade splunk to 8.1.5 or later.

CVE & CISA-KEV Catalog

CVE-2021-31559

HIGH

7.5

CVSS v3

NVD

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.

CWE-288

How to fix

Remediation Available

splunkNVD

Affected:>= 8.1.0, < 8.1.5Fixed in:8.1.5CVE-2021-31559derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploit Intelligence

0.83%probability of exploitation in 30 days

53rdpercentile

Moderate risk: more likely to be exploited than 53% of all known CVEs.

References

Vendor Advisory1

splunk.com

Related Vulnerabilities

Other CWE-288 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-42793	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2024-1709	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2024-27198	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2025-4427	Medium	5.3	100%	KEV	Fix
CVE-2024-55591	Critical	9.8	98%	KEV + Ransom	Fix
CVE-2023-46747	Critical	9.8	97%	KEV + Ransom	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.