CVE-2026-27627Public exploitNetwork attack vector

Stored XSS via unsanitized Reddit content

Published Feb 25, 2026 · Updated Feb 25, 2026

Stored XSS in Karakeep 0.30.0 allows remote attackers to execute JavaScript when a user opens a crafted Reddit bookmark in reader view. The Reddit metascraper decodes selftext_html and stores readableContentHtml without DOMPurify before the reader renders it through dangerouslySetInnerHTML. Exploitation requires a user to save and open attacker-controlled Reddit-like content; the script then runs in that user's session and can read data or act with that user's permissions.

CVSS severity8.2
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Karakeep 0.30.0 allows remote attackers to execute JavaScript when a user opens a crafted Reddit bookmark in reader view. The Reddit metascraper decodes selftext_html and stores readableContentHtml without DOMPurify before the reader renders it through dangerouslySetInnerHTML. Exploitation requires a user to save and open attacker-controlled Reddit-like content; the script then runs in that user's session and can read data or act with that user's permissions.

The record

CVE
CVE-2026-27627
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
Localhost Labs Ltd
Product
Karakeep
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion== 0.30.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Localhost Labs Ltd · Karakeepversion== 0.30.0

Published CVSS scores

8.2GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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