VulnerabilityPublished 25 Feb 2026

CVE-2026-27627: karakeep · Cross-site Scripting

Affects karakeepSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

8.2High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% 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:H/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: High
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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 25 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity 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
karakeep-appkarakeep	Affected =0.30.0	Fixed in–
GitHubkarakeep-app/karakeep`pkg:github/karakeep-app/karakeep`Other threats	Affected =0.30.0	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 this vulnerability, organizations should immediately upgrade karakeep to version 0.31.0 or later, where the Reddit metascraper plugin's output is properly sanitized using DOMPurify. If upgrading is not immediately feasible, administrators should consider disabling the Reddit metascraper plugin to prevent untrusted HTML content from being rendered. Implement additional input validation and sanitization layers on all third-party content sources before rendering. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. Educate users about the risks of interacting with untrusted content and encourage cautious behavior when viewing dynamically generated content. Regularly audit and monitor logs for unusual activity that may indicate exploitation attempts. For developers, avoid using `dangerouslySetInnerHTML` without thorough sanitization and prefer safer rendering methods. Incorporate automated security testing and code reviews focusing on input handling and sanitization consistency across all content sources.

Description

Karakeep is a elf-hostable bookmark-everything app. In version 0.30.0, when the Reddit metascraper plugin returns `readableContentHtml`, the HTML parsing subprocess uses it directly without running it through DOMPurify. Every other content source in the crawler goes through Readability + DOMPurify, but the Reddit path skips both. Since this content ends up in `dangerouslySetInnerHTML` in the reader view, any malicious HTML in the Reddit response gets executed in the user's browser. Version 0.31.0 contains a patch for this issue.

Impact

The primary impact of this vulnerability is the potential compromise of user confidentiality and partial integrity through cross-site scripting attacks. Attackers can inject malicious scripts that execute in the context of the victim's browser, potentially stealing authentication tokens, cookies, or other sensitive data. This can lead to unauthorized access to user accounts or data leakage. The integrity of displayed content may be altered, misleading users or enabling phishing attacks. Although availability is not directly affected, successful exploitation could facilitate further attacks that degrade service or user trust. Organizations using karakeep 0.30.0, especially those self-hosting the application for internal or external users, face risks of targeted attacks if adversaries craft malicious Reddit content or manipulate the metascraper responses. The requirement for user interaction (viewing the malicious content) somewhat limits automated exploitation but does not eliminate risk, especially in environments where users frequently consume Reddit content via karakeep. The vulnerability could be leveraged in spear-phishing campaigns or supply chain attacks targeting organizations relying on karakeep for bookmark management. Given the high CVSS score and the widespread use of web applications integrating third-party content, the potential impact is significant for confidentiality and user trust.

Summary

CVE-2026-27627 is a cross-site scripting vulnerability classified under CWE-79 affecting karakeep, a self-hostable bookmark management application, specifically version 0.30.0. The vulnerability stems from improper neutralization of input during web page generation. Karakeep uses a Reddit metascraper plugin to fetch content, which returns HTML in the field `readableContentHtml`. Unlike other content sources that undergo sanitization via Readability and DOMPurify to remove malicious scripts, the Reddit path bypasses these sanitization steps. Consequently, the HTML content is directly injected into the React component using `dangerouslySetInnerHTML` in the reader view. This direct injection allows any malicious HTML or JavaScript embedded in the Reddit response to execute in the context of the user's browser session. The vulnerability has a CVSS 3.1 base score of 8.2, indicating high severity, with an attack vector of network (remote), low attack complexity, no privileges required, but requiring user interaction (viewing the malicious content). The scope is changed, affecting confidentiality (high impact), integrity (low impact), but not availability. The flaw could lead to theft of sensitive information such as cookies, session tokens, or other browser-stored data, and potentially enable further attacks like session hijacking or phishing. The issue was addressed in karakeep version 0.31.0 by ensuring that the Reddit metascraper plugin's HTML output is properly sanitized through DOMPurify before rendering. No known exploits have been reported in the wild as of the publication date. The vulnerability highlights the risks of inconsistent input sanitization in web applications, especially when integrating third-party content sources.

CWE-79Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Mar 2026, 20:34 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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