How severe is CVE-2026-20253?

CVE-2026-20253 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-20253 being actively exploited?

Yes. CVE-2026-20253 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-06-18, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2026-20253?

CVE-2026-20253 affects Splunk. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-20253?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2026-20253 have an EU (EUVD) identifier?

Yes. CVE-2026-20253 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36088. It is also flagged as exploited in the EUVD (since 2026-06-18).

When was CVE-2026-20253 published?

CVE-2026-20253 was published on 2026-06-10 and last updated on 2026-07-23.

CVE-2026-20253

CVE-2026-20253 is a critical-severity vulnerability in Splunk with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-06-18). The underlying weakness is classified as CWE-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 97% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-06-18)
EU (EUVD) id: EUVD-2026-36088
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2026-06-18)
Weakness: CWE-306
Affected product: Splunk
Published: 2026-06-10
Last modified: 2026-07-23

Description

In Splunk Enterprise 10.2 versions below 10.2.4 and 10 versions below 10.0.7, an unauthenticated user could create or truncate arbitrary files through a PostgreSQL sidecar service endpoint. The vulnerability exists because the PostgreSQL sidecar service endpoint lacks authentication controls, allowing any network-reachable user to invoke file operations without credentials. Splunk Enterprise versions 9.4 and earlier are not affected. If you cannot immediately upgrade to a fixed version, you can mitigate this vulnerability by disabling the PostgreSQL sidecar service.

Frequently asked questions

What is CVE-2026-20253?: In Splunk Enterprise 10.2 versions below 10.2.4 and 10 versions below 10.0.7, an unauthenticated user could create or truncate arbitrary files through a PostgreSQL sidecar service endpoint. The vulnerability exists because the PostgreSQL sidecar service endpoint lacks authentication controls, allowing any network-reachable user to invoke file operations without credentials. Splunk Enterprise versions 9.4 and earlier are not affected. If you cannot immediately upgrade to a fixed version, you can mitigate this vulnerability by disabling the PostgreSQL sidecar service.
How severe is CVE-2026-20253?: CVE-2026-20253 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-20253 being actively exploited?: Yes. CVE-2026-20253 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-06-18, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-20253?: CVE-2026-20253 affects Splunk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-20253?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2026-20253 have an EU (EUVD) identifier?: Yes. CVE-2026-20253 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36088. It is also flagged as exploited in the EUVD (since 2026-06-18).
When was CVE-2026-20253 published?: CVE-2026-20253 was published on 2026-06-10 and last updated on 2026-07-23.

References

Affected products (1)

cpe:2.3:a:splunk:splunk:*:*:*:*:enterprise:*:*:*

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