CVE-2026-23768VulnerabilityPublished 16 Jan 2026

CVE-2026-23768: NAVER lucy-xss-filter · Server-Side Request Forgery (SSRF)

Affects NAVER lucy-xss-filterSource CVE Database V5

Not known to be exploited · CVSS 6.1 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

6.1Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: Low
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to 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 16 Jan 2026
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 2026-10-25.

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
NAVERlucy-xss-filter	Affected–	Fixed in–
GitHublucy-xss-filter`pkg:github/lucy-xss-filter`Other threats	Affected–	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-23768, organizations should first identify all deployments of lucy-xss-filter within their environments. If updating is not immediately feasible, temporarily disable the ObjectSecurityListener and EmbedSecurityListener options, which are the vulnerable features triggering SSRF. Additionally, implement strict validation and sanitization of all embed and object tag src attributes, ensuring they include valid file extensions and conform to expected URL patterns. Employ network-level controls such as egress filtering and segmentation to limit the server's ability to make arbitrary outbound HTTP requests, reducing the impact of potential SSRF exploitation. Monitor server logs for unusual HEAD requests or unexpected outbound connections. Finally, incorporate SSRF detection mechanisms in web application firewalls (WAFs) and conduct regular security assessments focusing on SSRF vectors.

Description

lucy-xss-filter before commit 7c1de6d allows an attacker to induce server-side HEAD requests to arbitrary URLs when the ObjectSecurityListener or EmbedSecurityListener option is enabled and embed or object tags are used with a src attribute missing a file extension.

Impact

For European organizations, this SSRF vulnerability poses significant risks, especially for those deploying NAVER's lucy-xss-filter in web applications exposed to untrusted users or the internet. Exploitation could allow attackers to perform unauthorized internal network scans, access sensitive internal services such as databases, metadata endpoints, or administrative interfaces, and potentially exfiltrate confidential information. This could lead to data breaches, service disruptions, or facilitate lateral movement within corporate networks. Organizations in sectors with strict data protection regulations, such as finance, healthcare, and government, may face compliance violations if internal data is exposed. Additionally, SSRF can be a stepping stone for more complex attacks, including remote code execution or privilege escalation, if combined with other vulnerabilities. The lack of authentication requirements and the ease of triggering the vulnerability increase the risk profile. Although no known exploits exist currently, the potential impact on confidentiality and availability is high, warranting urgent attention from affected entities.

CWE-918Server-Side Request Forgery (SSRF) (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 16 Jan 2026, 05:42 UTC

WeaknessesCWE-918

Technical details

References

Community reviews

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