CVE-2025-20384VulnerabilityPublished 3 Dec 2025

CVE-2025-20384: Splunk Enterprise · The software does not neutralize or incorrectly neutralizes output that is written to logs.

Affects Splunk EnterpriseSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Splunk Splunk Enterprise	Affected =10.0 =9.4 =9.3 =9.2	Fixed in–

AI-suggested

Organizations should prioritize upgrading Splunk Enterprise and Splunk Cloud Platform to versions 10.0.1 or later, 9.4.6 or later, 9.3.8 or later, and 9.2.10 or later as applicable. Until upgrades are applied, implement strict web application firewall (WAF) rules to detect and block HTTP requests containing suspicious ANSI escape sequences targeting the /en-US/static/ endpoint. Enhance log monitoring to identify anomalies indicative of log poisoning, such as unexpected control characters or formatting irregularities. Review and harden input validation and output encoding mechanisms in custom Splunk apps or integrations that interact with user-supplied data. Conduct regular audits of log integrity using cryptographic methods or third-party tools to detect tampering. Train security analysts to recognize signs of log manipulation and incorporate this threat into incident response playbooks. Coordinate with Splunk support and monitor vendor advisories for patches and updates. Consider network segmentation and limiting exposure of Splunk management interfaces to reduce attack surface.

Description

In Splunk Enterprise versions below 10.0.1, 9.4.6, 9.3.8, and 9.2.10, and Splunk Cloud Platform versions below 10.1.2507.4, 10.0.2503.6, and 9.3.2411.117.125, an unauthenticated attacker can inject American National Standards Institute (ANSI) escape codes into Splunk log files due to improper validation at the /en-US/static/ web endpoint. This may allow them to poison, forge, or obfuscate sensitive log data through specially crafted HTTP requests, potentially impacting log integrity and detection capabilities.

Impact

For European organizations, this vulnerability threatens the integrity of security logs, which are essential for detecting malicious activity, conducting forensic investigations, and maintaining compliance with regulations such as GDPR and NIS Directive. Log poisoning can cause false negatives or false positives in security monitoring, delaying or preventing detection of real attacks. Critical sectors like finance, energy, telecommunications, and government that rely heavily on Splunk for centralized log management and security analytics are particularly vulnerable. The inability to trust log data can undermine incident response and risk management processes, potentially leading to prolonged breaches or regulatory penalties. Since exploitation requires no authentication and can be performed remotely, the attack surface is broad, increasing the likelihood of opportunistic attacks. However, the lack of known exploits and the medium severity rating suggest the threat is moderate but should not be underestimated in high-risk environments.

Summary

CVE-2025-20384 is a vulnerability identified in Splunk Enterprise versions prior to 10.0.1, 9.4.6, 9.3.8, and 9.2.10, as well as corresponding versions of Splunk Cloud Platform. The root cause is the failure to properly neutralize or sanitize output written to log files, specifically allowing injection of ANSI escape codes through the /en-US/static/ web endpoint. ANSI escape codes can manipulate terminal output, enabling attackers to alter how log entries are displayed or interpreted. An unauthenticated attacker can craft HTTP requests containing these escape codes, which get logged by Splunk without adequate sanitization. This results in log poisoning, where log entries can be forged or obfuscated, potentially misleading security analysts or automated detection systems. The vulnerability does not impact confidentiality or availability directly but compromises the integrity of log data, a critical component for security monitoring and incident response. The CVSS 3.1 base score is 5.3, reflecting network attack vector, low complexity, no privileges required, no user interaction, and impact limited to integrity. No public exploits have been reported yet, but the vulnerability poses a risk to organizations relying on Splunk for trustworthy log data.

References

advisory.splunk.com/advisories/SVD-2025-1203 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Dec 2025, 18:33 UTC

Technical details

References

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