CVE-2026-45539
Microsoft APM: Symlinks under `.apm/prompts/` and `.apm/agents/` are dereferenced during `apm install`, copying host-local file contents into the project tree
Description
Microsoft APM is an open-source, community-driven dependency manager for AI agents. From 0.5.4 to 0.12.4, two primitive integrators in apm-cli enumerate package files with bare Path.glob() / Path.rglob() calls and read each match with Path.read_text(), transparently following symbolic links. A symlink committed inside a remote APM dependency under .apm/prompts/<x>.prompt.md or .apm/agents/<x>.agent.md is preserved verbatim into apm_modules/ on clone and then dereferenced during integration, with the resolved content written as a regular file into the project's deploy directories. The package content_hash, the pre-deploy SecurityGate scan, and apm audit do not flag this. The deploy roots are not added to the auto-generated .gitignore, so the resulting files are staged by git add by default. This vulnerability is fixed in 0.13.0.
INFO
Published Date :
May 15, 2026, 5:16 p.m.
Last Modified :
Oct. 26, 2026, 2:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-45539
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 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Microsoft APM to version 0.13.0.
- Verify gitignore configuration.
- Remove staged malicious files.
Public PoC/Exploit Available at Github
CVE-2026-45539 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-2026-45539.
| URL | Resource |
|---|---|
| https://github.com/microsoft/apm/security/advisories/GHSA-q5pp-gvjg-h7v4 | |
| https://github.com/microsoft/apm/security/advisories/GHSA-q5pp-gvjg-h7v4 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45539 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-2026-45539
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).
None
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45539 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45539 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.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: apm de microsoft, Description: Microsoft APM es un gestor de dependencias de código abierto, impulsado por la comunidad, para agentes de IA. Desde la versión 0.5.4 hasta la 0.12.4, dos integradores primitivos en apm-cli enumeran archivos de paquete con llamadas directas a Path.glob() / Path.rglob() y leen cada coincidencia con Path.read_text(), siguiendo de forma transparente los enlaces simbólicos. Un enlace simbólico (symlink) comprometido dentro de una dependencia APM remota bajo .apm/prompts/[x].prompt.md o .apm/agents/[x].agent.md se conserva literalmente en apm_modules/ al clonar y luego se desreferencia durante la integración, con el contenido resuelto escrito como un archivo regular en los directorios de despliegue del proyecto. El content_hash del paquete, el escaneo SecurityGate previo al despliegue y la auditoría de apm no marcan esto. Las raíces de despliegue no se añaden al .gitignore auto-generado, por lo que los archivos resultantes son preparados por git add por defecto. Esta vulnerabilidad está corregida en la versión 0.13.0. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'microsoft', 'product': 'apm', 'versions': [{'status': 'affected', 'version': '>= 0.5.4, < 0.13.0'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-45539', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-15T16:41:16.377667Z'} -
New CVE Received by [email protected]
May. 15, 2026
Action Type Old Value New Value Added Description Microsoft APM is an open-source, community-driven dependency manager for AI agents. From 0.5.4 to 0.12.4, two primitive integrators in apm-cli enumerate package files with bare Path.glob() / Path.rglob() calls and read each match with Path.read_text(), transparently following symbolic links. A symlink committed inside a remote APM dependency under .apm/prompts/<x>.prompt.md or .apm/agents/<x>.agent.md is preserved verbatim into apm_modules/ on clone and then dereferenced during integration, with the resolved content written as a regular file into the project's deploy directories. The package content_hash, the pre-deploy SecurityGate scan, and apm audit do not flag this. The deploy roots are not added to the auto-generated .gitignore, so the resulting files are staged by git add by default. This vulnerability is fixed in 0.13.0. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N Added CWE CWE-200 Added CWE CWE-59 Added Reference https://github.com/microsoft/apm/security/advisories/GHSA-q5pp-gvjg-h7v4 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 15, 2026
Action Type Old Value New Value Added Reference https://github.com/microsoft/apm/security/advisories/GHSA-q5pp-gvjg-h7v4