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Full vulnerability report · 2026
CVE-2026-76404High confidence

Remote Code Execution (RCE) through Deserialization of Untrusted Data in Splunk MCP Server app

Splunk · Splunk MCP Server app

9.1CriticalCVSS 3.1
Recommended action
Within 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-62969

No EUVD known-exploited evidence

In Splunk MCP Server app versions below 1.2.1, a user who holds the "admin" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app's credential management component, which deserializes stored data without checking whether the content is of the expected type.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
9.1 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

In Splunk MCP Server app versions below 1.2.1, a user who holds the "admin" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app's credential management component, which deserializes stored data without checking whether the content is of the expected type.

What

In Splunk MCP Server app versions below 1.2.1, a user who holds the "admin" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app's credential management component, which deserializes stored data without checking whether the content is of the expected type.

Why

Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may execute code or commands in the affected security context.

What

In Splunk MCP Server app versions below 1.2.1, a user who holds the "admin" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app's credential management component, which deserializes stored data without checking whether the content is of the expected type.

Why

Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may execute code or commands in the affected security context.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Deserialization of Untrusted Data → execute code or commands in the affected security context
Attack surface
Network
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-502 ↗

CWE-502: Deserialization of Untrusted Data. The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
NetworkRemote code executionCWE-502
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-62969Official EUVD mapping

In Splunk MCP Server app versions below 1.2.1, a user who holds the "admin" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app's credential management component, which deserializes stored data without checking whether the content is of the expected type.

Official EUVD record
CERT-FR · French · CERTFR-2026-AVI-1056Multiples vulnérabilités dans les produits Splunk

d?id=CVE-2026-76395 Référence CVE CVE-2026-76396 https://www.cve.org/CVERecord?id=CVE-2026-76396 Référence CVE CVE-2026-76397 https://www.cve.org/CVERecord?id=CVE-2026-76397 Référence CVE CVE-2026-76398 https://www.cve.org/CVERecord?id=CVE-2026-76398 Référence CVE CVE-2026-76399 https://www.cve.org/CVERecord?id=CVE-2026-76399 Référence CVE CVE-2026-76400 https://www.cve.org/CVERecord?id=CVE-2026-76400 Référence CVE CVE-2026-76401 https://www.cve.org/CVERecord?id=CVE-2026-76401 Référence CVE CVE-2026-76402 https://www.cve.org/CVERecord?id=CVE-2026-76402 Référence CVE CVE-2026-76403 https://www.cve.org/CVERecord?id=CVE-2026-76403 Référence CVE CVE-2026-76404 https://www.cve.org/CVERecord?id=CVE-2026-76404 Référence CVE CVE-2026-76405 https://www.cve.org/CVERecord?id=CVE-2026-76405 Référence CVE CVE-2026-9076 https://www.cve.org/CVERecord?id=CVE-2026-9076 Référence CVE CVE-2026-9256 https://www.cve.org/CVERecord?id=CVE-2026-9256 Gestion détaillée du document le 20 août 2026 Version initiale Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À propos Contact cyber.gouv.fr service-public.fr legifrance.gouv.fr info.gouv.fr france.fr info.gouv.fr/risques Premier Ministre / Secrétariat Général de la Défense et de la Sécurité Nationale / Agence nationale de la sécurité des systèm

Official advisory
CSIRT Italia · Italian · vulnerabilita-in-prodotti-splunk-5Vulnerabilità in prodotti Splunk

recedenti 10.0.x, versione 10.0.8 e precedenti 9.4.x, versione 9.4.13 e precedenti Splunk MCP Server app 1.2.x, versioni precedenti alla 1.2.1 Splunk Connect for Kafka 2.2.x, versioni precedenti alla 2.2.7 Cisco Talos Intelligence for Enterprise Security Cloud 1.0.x, versioni precedenti alla 1.0.3 Azioni di mitigazione In linea con le dichiarazioni del vendor, si raccomanda di aggiornare i prodotti vulnerabili seguendo le indicazioni dei bollettini di sicurezza riportati nella sezione Riferimenti. Di seguito sono riportate le sole CVE relative alle vulnerabilità con gravità “critica” e “alta”: CVE (44) Cerca: Tabella CVE CVE POC EXPLOITATION CVE-2026-76404 : apre una nuova finestra - - CVE-2026-76403 : apre una nuova finestra - - CVE-2026-76402 : apre una nuova finestra - - CVE-2026-76399 : apre una nuova finestra - - CVE-2026-76397 : apre una nuova finestra - - CVE-2026-76396 : apre una nuova finestra - - CVE-2026-76395 : apre una nuova finestra - - CVE-2026-76394 : apre una nuova finestra - - CVE-2026-76391 : apre una nuova finestra - - CVE-2026-76389 : apre una nuova finestra - - CVE-2026-76388 : apre una nuova finestra - - CVE-2026-76387 : apre una nuova finestra - - CVE-2026-76362 : apre una nuova finestra - - CVE-2026-76357 : apre una nuova finestra - - CVE-2026-76356 : apre una nuova fi

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
1.2 < 1.2.1
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 19 Aug 2026 · Last source change 20 Aug 2026, 15:26 UTC · CWE-502 · Deserialization of Untrusted Data

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-23
European sourceENISA EUVD · EUVD-2026-62969
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →
  1. Vendor guidanceAuthoritative vendor guidance changed from no authoritative guidance recorded to vendor advisory.
    Before
    no authoritative guidance recorded
    After
    vendor advisory
    psirt@cisco.com ↗
  2. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-62969↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-76404 · cve.blacktree.nl