CVE-2026-20251: Remote Code Execution through Deserialization of Untrusted Data in Splunk Secure Gateway

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 28 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

32.2%

EPSS score, percentile 98.3 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

8.8 High

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• from 10.2 to before 10.2.4
• from 10.0 to before 10.0.7
• from 9.4 to before 9.4.12
• from 9.3 to before 9.3.13
• from 10.3.2512 to before 10.3.2512.12
• from 10.2.2510 to before 10.2.2510.14

and 5 more in the table below

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, Splunk Cloud Platform versions below 10.3.2512.12, 10.2.2510.14, 10.1.2507.22, and 9.3.2411.132, and Splunk Secure Gateway versions below 3.10.6, 3.9.20, and 3.8.67, a low-privileged user that does not hold the 'admin' or 'power' Splunk roles could perform a Remote Code Execution (RCE) through the Splunk Secure Gateway app.<b…

Summary: CVE record, as of 28 Oct 2026.

• CISA has not added CVE-2026-20251 to its Known Exploited Vulnerabilities (KEV) catalog, as of 28 Oct 2026.
• The CVE record was published on 10 Jun 2026.
• The CVE record carries a CVSS v3.1 base score of 8.8 (High), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 32.2% (percentile 98.3), as of 28 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

Remote Code Execution through Deserialization of Untrusted Data in Splunk Secure Gateway

In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, Splunk Cloud Platform versions below 10.3.2512.12, 10.2.2510.14, 10.1.2507.22, and 9.3.2411.132, and Splunk Secure Gateway versions below 3.10.6, 3.9.20, and 3.8.67, a low-privileged user that does not hold the 'admin' or 'power' Splunk roles could perform a Remote Code Execution (RCE) through the Splunk Secure Gateway app.<br><br>The Remote Code Execution is possible because of unsafe deserialization of App Key Value Store (KV Store) data through the ‘jsonpickle’ Python library, which reconstructs arbitrary Python objects from specially crafted JavaScript Object Notation (JSON) without adequate validation.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-502

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

References

• advisory.splunk.com

Known exploited Splunk vulnerabilities

• CVE-2026-20253: Splunk Enterprise Missing Authentication for Critical Function Vulnerability (added 18 Jun 2026)