CVE-2026-15311: NousResearch hermes-agent Matrix Adapter matrix.py MatrixAdapter._markdown_to_html cross site scripting
A vulnerability was identified in NousResearch hermes-agent up to 2026.5.29.2. Affected by this issue is the function MatrixAdapter.markdowntohtml of the file gateway/platforms/matrix.py of the component Matrix Adapter. Such manipulation leads to cross site scripting. The attack can be executed remotely. The exploit is publicly available and might be used. The pull request to fix this issue awaits acceptance.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-15311?
The severity of CVE-2026-15311 is rated low with a score of 3.5.
What type of vulnerability is CVE-2026-15311?
CVE-2026-15311 is a cross site scripting (XSS) vulnerability.
How do I fix CVE-2026-15311?
To fix CVE-2026-15311, you should update the NousResearch hermes-agent to version 2026.5.29.3 or later.
What component is affected by CVE-2026-15311?
CVE-2026-15311 affects the MatrixAdapter._markdown_to_html function in the matrix.py file of the Matrix Adapter.
When was CVE-2026-15311 published?
CVE-2026-15311 was published on July 9, 2026.