CVE-2026-29964
HSC MailInspector Cross-Site Scripting (XSS)
Description
HSC MailInspector v5.3.3-7 contains a Cross-Site Scripting (XSS) vulnerability in the /tap/tap.php endpoint due to improper neutralization of user-controlled input using alternate or obfuscated JavaScript syntax. The endpoint reflects unsanitized user input in HTTP responses without adequate output encoding, allowing a remote attacker to execute arbitrary JavaScript code in the context of a victim's browser.
INFO
Published Date :
May 18, 2026, 6:17 p.m.
Last Modified :
May 19, 2026, 5:20 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update HSC MailInspector to the latest version.
- Ensure user input is properly sanitized.
- Encode output to prevent script execution.
Public PoC/Exploit Available at Github
CVE-2026-29964 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
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-2026-29964.
| URL | Resource |
|---|---|
| https://github.com/sql3t0/cve-disclosures | Third Party Advisory |
| https://github.com/sql3t0/cve-disclosures/blob/main/03_-_CVE-2026-29964_XSS.md | Third Party Advisory |
| https://hsclabs.com/pt-br/mailinspector/ | Product |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-29964 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-2026-29964
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).
Collection of CVEs and security advisories discovered and responsibly disclosed by Sql3t0, including technical details, impact assessment, and mitigation guidance.
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-29964 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-29964 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.
-
Initial Analysis by [email protected]
May. 19, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:hsclabs:mailinspector:5.3.3-7:*:*:*:*:*:*:* Added Reference Type MITRE: https://github.com/sql3t0/cve-disclosures Types: Third Party Advisory Added Reference Type MITRE: https://github.com/sql3t0/cve-disclosures/blob/main/03_-_CVE-2026-29964_XSS.md Types: Third Party Advisory Added Reference Type MITRE: https://hsclabs.com/pt-br/mailinspector/ Types: Product -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Added CWE CWE-79 -
New CVE Received by [email protected]
May. 18, 2026
Action Type Old Value New Value Added Description HSC MailInspector v5.3.3-7 contains a Cross-Site Scripting (XSS) vulnerability in the /tap/tap.php endpoint due to improper neutralization of user-controlled input using alternate or obfuscated JavaScript syntax. The endpoint reflects unsanitized user input in HTTP responses without adequate output encoding, allowing a remote attacker to execute arbitrary JavaScript code in the context of a victim's browser. Added Reference https://github.com/sql3t0/cve-disclosures Added Reference https://github.com/sql3t0/cve-disclosures/blob/main/03_-_CVE-2026-29964_XSS.md Added Reference https://hsclabs.com/pt-br/mailinspector/