XSS Vulnerability in Remark42 Comment Engine
CVE-2026-48788

8.2HIGH

Key Information:

Vendor

Umputun

Status
Remark42
Vendor
CVE Published:
16 June 2026

What is CVE-2026-48788?

Remark42, a self-hosted comment engine, is vulnerable to a Cross-Site Scripting attack due to improper handling of Content-Type headers during image proxying. Versions 1.6.0 through 1.15.0 allow an attacker to exploit this by serving a malicious URL that masquerades as an image. The proxy accepts the image based solely on the advertised Content-Type, without verifying the actual content. This inconsistency enables an attacker to manipulate the serving process, leading to the execution of arbitrary HTML/JavaScript within the context of the Remark42 instance. To mitigate this issue, upgrade to version 1.16.0 or later.

Affected Version(s)

remark42 >= 1.6.0, < 1.16.0

References

https://github.com/umputun/remark42/security/advisories/G...
x_refsource_CONFIRM
https://github.com/umputun/remark42/commit/78d6de6bce1e96...
x_refsource_MISC
https://github.com/umputun/remark42/releases/tag/v1.16.0
x_refsource_MISC

CVSS V3.0

Score:
8.2
Severity:
HIGH
Confidentiality:
High
Integrity:
Low
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.