CVE-2026-48788Public exploitNetwork attack vector

Cross-site scripting via image proxy type confusion

Published Jun 16, 2026 · Updated Jun 16, 2026

Cross-site scripting in Remark42 1.6.0 through 1.15.0 allows remote attackers to execute script in its origin via a proxy link. The /api/v1/img downloader trusts an upstream image Content-Type without validating the body, while the serving path sniffs the bytes and labels an HTML body as text/html. No account is required, but a victim must open the crafted link; the script can act with the victim's session, including administrative access when the victim is an administrator.

CVSS severity8.2
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Remark42 1.6.0 through 1.15.0 allows remote attackers to execute script in its origin via a proxy link. The /api/v1/img downloader trusts an upstream image Content-Type without validating the body, while the serving path sniffs the bytes and labels an HTML body as text/html. No account is required, but a victim must open the crafted link; the script can act with the victim's session, including administrative access when the victim is an administrator.

The record

CVE
CVE-2026-48788
Published
Jun 16, 2026
Updated
Jun 16, 2026
Vendor
Remark42
Product
Remark42
Classifications
CWE-79, CWE-436, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 1.6.0, < 1.16.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Remark42 · Remark42version=>= 1.6.0, < 1.16.0

Published CVSS scores

8.2GitHub, Inc.CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
CWE-436Interpretation Conflict
T1189Drive-by Compromise

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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