How severe is CVE-2026-20204?

CVE-2026-20204 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-20204 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-20204?

CVE-2026-20204 primarily affects Splunk. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-20204?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-20204 have an EU (EUVD) identifier?

Yes. CVE-2026-20204 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22934.

When was CVE-2026-20204 published?

CVE-2026-20204 was published on 2026-04-15 and last updated on 2026-06-17.

CVE-2026-20204

CVE-2026-20204 is a high-severity vulnerability in Splunk with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-377.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-22934
Weakness: CWE-377
Affected product: Splunk
Published: 2026-04-15
Last modified: 2026-06-17

Description

In Splunk Enterprise versions below 10.2.1, 10.0.5, 9.4.10, and 9.3.11, and Splunk Cloud Platform versions below 10.4.2603.0, 10.3.2512.5, 10.2.2510.9, 10.1.2507.19, 10.0.2503.13, and 9.3.2411.127, a low-privileged user that does not hold the `admin` or `power` Splunk roles could potentially perform a Remote Code Execution (RCE) by uploading a malicious file to the `$SPLUNK_HOME/var/run/splunk/apptemp` directory due to improper handling and insufficient isolation of temporary files within the `apptemp` directory.

Frequently asked questions

What is CVE-2026-20204?: In Splunk Enterprise versions below 10.2.1, 10.0.5, 9.4.10, and 9.3.11, and Splunk Cloud Platform versions below 10.4.2603.0, 10.3.2512.5, 10.2.2510.9, 10.1.2507.19, 10.0.2503.13, and 9.3.2411.127, a low-privileged user that does not hold the `admin` or `power` Splunk roles could potentially perform a Remote Code Execution (RCE) by uploading a malicious file to the `$SPLUNK_HOME/var/run/splunk/apptemp` directory due to improper handling and insufficient isolation of temporary files within the `apptemp` directory.
How severe is CVE-2026-20204?: CVE-2026-20204 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-20204 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-20204?: CVE-2026-20204 primarily affects Splunk. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-20204?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-20204 have an EU (EUVD) identifier?: Yes. CVE-2026-20204 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22934.
When was CVE-2026-20204 published?: CVE-2026-20204 was published on 2026-04-15 and last updated on 2026-06-17.

References

https://advisory.splunk.com/advisories/SVD-2026-0403

Affected products (3)

cpe:2.3:a:splunk:splunk:*:*:*:*:enterprise:*:*:*
cpe:2.3:a:splunk:splunk:10.2.0:*:*:*:enterprise:*:*:*
cpe:2.3:a:splunk:splunk_cloud_platform:*:*:*:*:*:*:*:*

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Other CWE-377 (Insecure Temporary File) vulnerabilities

CVE-2011-4119 — Critical (CVSS 9.8): caml-light <= 0.75 uses mktemp() insecurely, and also does unsafe things in /tmp during make install.
CVE-2012-2666 — Critical (CVSS 9.8): golang/go in 1.0.2 fixes all.bash on shared machines. dotest() in src/pkg/debug/gosym/pclntab_test.go creates a…
CVE-2015-5224 — Critical (CVSS 9.8): The mkostemp function in login-utils in util-linux when used incorrectly allows remote attackers to cause file name…
CVE-2025-14307 — High (CVSS 8.1): An insecure temporary file creation vulnerability exists in the AutoExtract component of Robocode version 1.9.3.6. The…
CVE-2023-43498 — High (CVSS 8.1): In Jenkins 2.423 and earlier, LTS 2.414.1 and earlier, processing file uploads using MultipartFormDataParser creates…
CVE-2025-46369 — High (CVSS 7.8): Dell Alienware Command Center 6.x (AWCC), versions prior to 6.10.15.0, contains an Insecure Temporary File…

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