CVE-2026-54521
FairEmail: Cross-site scripting (XSS) in AMP message rendering (ActivityAMP)
Description
FairEmail is a fully featured, open source, privacy-friendly email app for Android. Prior to 1.2319, the ActivityAMP AMP message renderer in app/src/main/java/eu/faircode/email/ActivityAMP.java enables JavaScript in its WebView but incompletely sanitizes untrusted message HTML. For non-allowlisted hosts, script.removeAttr("src") leaves inline script elements in the document and does not reject event-handler attributes or javascript: URLs on other elements. A crafted AMP email can execute arbitrary JavaScript when a recipient opens the message and enables the AMP toggle. The script can read the message DOM, exfiltrate message data, and display phishing overlays within the message-body area. Exploitation requires the recipient to enable the AMP toggle, and practical exposure is reduced because AMP email is uncommon. This issue is fixed in version 1.2319.
INFO
Published Date :
Sept. 17, 2026, 9:17 p.m.
Last Modified :
Sept. 17, 2026, 9:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-54521
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update FairEmail to version 1.2319 or later.
- Ensure AMP message rendering is properly sanitized.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54521.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54521 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54521
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54521 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54521 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Sep. 17, 2026
Action Type Old Value New Value Added Description FairEmail is a fully featured, open source, privacy-friendly email app for Android. Prior to 1.2319, the ActivityAMP AMP message renderer in app/src/main/java/eu/faircode/email/ActivityAMP.java enables JavaScript in its WebView but incompletely sanitizes untrusted message HTML. For non-allowlisted hosts, script.removeAttr("src") leaves inline script elements in the document and does not reject event-handler attributes or javascript: URLs on other elements. A crafted AMP email can execute arbitrary JavaScript when a recipient opens the message and enables the AMP toggle. The script can read the message DOM, exfiltrate message data, and display phishing overlays within the message-body area. Exploitation requires the recipient to enable the AMP toggle, and practical exposure is reduced because AMP email is uncommon. This issue is fixed in version 1.2319. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/54xxx/CVE-2026-54521.json">CVE-2026-54521</a> Added Reference https://github.com/M66B/FairEmail/commit/fb37bbfabf5e75d08f0cfa6ce9b84469d62a20a0 Added Reference https://github.com/M66B/FairEmail/releases/tag/1.2319 Added Reference https://github.com/M66B/FairEmail/security/advisories/GHSA-r8ff-qr7g-pvw6