Medium Input validation

CVE-2026-20255 — Improper Input Validation through Classic Dashboards in Splunk Enterprise

In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, and Splunk Cloud Platform versions below 10.3.2512.13, 10.2.2510.15, 10.1.2507.23, and 9.3.2411.132, a low-privileged user that does not hold the "admin" or "power" Splunk roles could craft a malicious classic dashboard that exfiltrates sensitive data to an external server. The vulnerability exists because URL validation on the external content dialog is incomplete, which can allow for requests to untrusted domains when a user interacts with a crafted dashboard.

Published Jun 10, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: cisco

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.4% (30-day exploitation probability)+4
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.35%

ahead of 27% of scored CVEs · Oct 14, 2026

Affects

Splunk

Splunk and 2 more

CVSS base

5.7

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Splunk Splunk, Splunk Splunk Cloud Platform, Splunk Splunk Enterprise).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (input validation), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Splunk	Splunk	≥ 9.3.0 and < 9.3.13≥ 9.4.0 and < 9.4.12≥ 10.0.0 and < 10.0.7≥ 10.2.0 and < 10.2.4	Vulnerable	NIST National Vulnerability Database
Splunk	Splunk Cloud Platform	≥ 9.3.2411 and < 9.3.2411.132≥ 10.1.2507 and < 10.1.2507.23≥ 10.2.2510 and < 10.2.2510.15≥ 10.3.2512 and < 10.3.2512.13	Vulnerable	NIST National Vulnerability Database
Splunk	Splunk Cloud Platform	≥ 10.3.2512 and < 10.3.2512.13≥ 10.2.2510 and < 10.2.2510.15≥ 10.1.2507 and < 10.1.2507.23≥ 9.3.2411 and < 9.3.2411.132	Vulnerable	CVE Program (cve.org) e CISA ADP
Splunk	Splunk Enterprise	≥ 10.2 and < 10.2.4≥ 10.0 and < 10.0.7≥ 9.4 and < 9.4.12≥ 9.3 and < 9.3.13	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

Low

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.7	CVSS 3.1	Medium	2.1	3.6	psirt@cisco.com via NIST National Vulnerability Database
5.7	CVSS 3.1	Medium	—	—	cisco via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N (score shown at the top: psirt@cisco.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-20 · Improper Input Validation

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.35%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · splunk/splunk enterprise, splunk/splunk cloud platform
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 5.7
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 10, 2026 · cisco

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

advisory.splunk.com/advisories/SVD-2026-0605
Vendor Advisory, NIST National Vulnerability Database

Elsewhere on this site

Splunk
every CVE for this vendor

Input validation
same class

CWE-20
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-76285 Improper Adherence to Coding Standards in Splunk Enterprise 8d
Critical CVE-2026-76284 Improper Neutralization in Splunk Enterprise 8d
Medium CVE-2026-76279 Improper Input Validation of Index Names through the collect Command in Splunk Enterprise 8d
Medium CVE-2026-76281 Improper Access Control in Splunk Enterprise 8d
Medium CVE-2026-76280 Incorrect Permission Assignment for App Key Value Store Collections in Splunk Secure Gateway 8d
Medium CVE-2026-76278 Authorization Bypass in SPL2 Module Permissions in Splunk Enterprise 8d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-20255 is "Improper Input Validation through Classic Dashboards in Splunk Enterprise", rated Medium. It affects Splunk (Splunk); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.7 describes technical severity. EPSS 0.35% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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