VULNpocalypse

CVE-2026-20253: Splunk Enterprise Missing Authentication for Critical Function Vulnerability

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

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.

Description quoted from the CVE record (assigned by cisco, published 2026-06-10).

Weakness: The software does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.

On CISA KEV since
2026-06-18
US federal deadline
2026-06-21
Ransomware use
Not known

Public exploit evidence (Exploit Observer)

Also known as: EUVD-2026-36088, GHSA-xgm5-jh99-wc4v

VEDAS cluster: VEDAS:DRAGONPOWDER

Exploit Observer links 12 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (12)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (1)

Vulnerability databases and vendor advisories (4)

Catalogue entries, not exploit evidence.

3 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.969
very likely to be attacked soon
VEDAS
0.985
strong exploit evidence
On CISA KEV
Yes, since 2026-06-18
Detection rule
Nuclei · Suricata
EPSS (chance of attack)
100.1CVE-2026-20253 EPSS over time2026-082026-11-01
VEDAS (exploit evidence)
100.9CVE-2026-20253 VEDAS over time2026-082026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish.

Who is affected

ProductAffectedNot affected
Splunk Splunk Enterprisefrom 10.2 before 10.2.4
from 10.0 before 10.0.7		Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: splunk splunk.

How to fix it

Fixed versions stated in the CVE record: 10.2.4, 10.0.7.

CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset’s internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Vendor guidance:

How to detect it

Nuclei template (active check)

Splunk Enterprise - Missing Authentication

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.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (POST /{{region}}/splunkd/__raw/v1/postgres/recovery/backup); it decides using status, word matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2026-20253.yaml
Show the template (40 lines)
yaml
id: CVE-2026-20253

info:
  name: "Splunk Enterprise - Missing Authentication"
  author: vedas-arpsyndicate
  severity: critical
  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.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-20253&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=splunk&match=exact
  classification:
    cve-id: CVE-2026-20253
  metadata:
    verified: false
  tags: cve,cve2026,splunk,postgres,backup,vkev,kev
http:
  - raw:
      - |
        POST /{{region}}/splunkd/__raw/v1/postgres/recovery/backup HTTP/1.1
        Host: {{Hostname}}
        Authorization: Basic ZGFnOg==

    payloads:
      region:
        - "en-US"

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "Failed to decode"

      - type: status
        status:
          - 400

CVE-2026-20253.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-20253 Splunk Enterprise - Missing Authentication. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-20253 Splunk Enterprise - Missing Authentication"; flow:established,to_client; file.data; content:"Failed to decode"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2026-20253; reference:url,https://www.exploit.observer/?keyword=CVE-2026-20253&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=splunk&match=exact; sid:1011566; rev:1;)

CVE-2026-20253.rules on GitHub

Advisories on this CVE

References

Exploits and technical analysis

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.