CVE-2026-55552
Yamcs: Unauthenticated Directory Traversal
Yamcs is a mission control framework. Prior to 5.11.13, Yamcs StaticFileHandler.locateFile resolves an unauthenticated request path without using Path.normalize and Path.toAbsolutePath to confirm that the absolute path remains within the configured staticRoots. A path containing traversal segments can escape the intended web root and return an arbitrary readable host file. The flaw is in yamcs-core/src/main/java/org/yamcs/http/StaticFileHandler.java and can disclose sensitive operating-system and application data. This issue is fixed in version 5.11.13, and the 5.12 line is fixed from version 5.12.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Yamcs: Unauthenticated Directory Traversal
Yamcs is a mission control framework. Prior to 5.11.13, Yamcs StaticFileHandler.locateFile resolves an unauthenticated request path without using Path.normalize and Path.toAbsolutePath to confirm that the absolute path remains within the configured staticRoots. A path containing traversal segments can escape the intended web root and return an arbitrary readable host file. The flaw is in yamcs-core/src/main/java/org/yamcs/http/StaticFileHandler.java and can disclose sensitive operating-system and application data. This issue is fixed in version 5.11.13, and the 5.12 line is fixed from version 5.12.0.
- Record
CVE-2026-55552- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
EUVDEUVD-2026-67842
Yamcs is a mission control framework. Prior to 5.11.13, Yamcs StaticFileHandler.locateFile resolves an unauthenticated request path without using Path.normalize and Path.toAbsolutePath to confirm that the absolute path remains within the configured staticRoots. A path containing traversal segments can escape the intended web root and return an arbitrary readable host file. The flaw is in yamcs-core/src/main/java/org/yamcs/http/StaticFileHandler.java and can disclose sensitive operating-system and application data. This issue is fixed in version 5.11.13, and the 5.12 line is fixed from version 5.12.0.
- Record
EUVD-2026-67842- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9jg3-g3wh-w9pj
Yamcs has Unauthenticated Directory Traversal
Attack type:
Unauthenticated remote
Impact:
Attackers can access any system files from the underlying host.
Affected components: HttpRequestHandler.java, StaticFileHandler.java
An Unauthenticated Directory Traversal vulnerability exists in Yamcs <=5.8.6, allowing anyone to access any file on the underlying operating system. This allows unauthenticated attackers to download sensitive files and data.
<img width="2170" height="1289" alt="image" src="https://github.com/user-attachments/assets/8d426da1-5351-4240-a290-8d858be61312" />
Steps to Reproduce:
- Start Yamcs and login as a user
- Paste the following URL in the browser and press enter:
http://localhost:8090//etc/passwd
- The
/etc/passwdfile will be downloaded.
Acknowledgements
This vulnerability was discovered by Abderrahim Dahmani while solving a STARPWN 2025 CTF challenge at DEFCON 33 offered by VisionSpace Technologies.
- Record
GHSA-9jg3-g3wh-w9pj- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
NVD
Yamcs is a mission control framework. Prior to 5.11.13, Yamcs StaticFileHandler.locateFile resolves an unauthenticated request path without using Path.normalize and Path.toAbsolutePath to confirm that the absolute path remains within the configured staticRoots. A path containing traversal segments can escape the intended web root and return an arbitrary readable host file. The flaw is in yamcs-core/src/main/java/org/yamcs/http/StaticFileHandler.java and can disclose sensitive operating-system and application data. This issue is fixed in version 5.11.13, and the 5.12 line is fixed from version 5.12.0.
- Record
CVE-2026-55552- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
OSV
Yamcs: Unauthenticated Directory Traversal
Yamcs is a mission control framework. Prior to 5.11.13, Yamcs StaticFileHandler.locateFile resolves an unauthenticated request path without using Path.normalize and Path.toAbsolutePath to confirm that the absolute path remains within the configured staticRoots. A path containing traversal segments can escape the intended web root and return an arbitrary readable host file. The flaw is in yamcs-core/src/main/java/org/yamcs/http/StaticFileHandler.java and can disclose sensitive operating-system and application data. This issue is fixed in version 5.11.13, and the 5.12 line is fixed from version 5.12.0.
- Record
CVE-2026-55552- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
OSVGHSA-9jg3-g3wh-w9pj
Yamcs has Unauthenticated Directory Traversal
Attack type:
Unauthenticated remote
Impact:
Attackers can access any system files from the underlying host.
Affected components: HttpRequestHandler.java, StaticFileHandler.java
An Unauthenticated Directory Traversal vulnerability exists in Yamcs <=5.8.6, allowing anyone to access any file on the underlying operating system. This allows unauthenticated attackers to download sensitive files and data.
<img width="2170" height="1289" alt="image" src="https://github.com/user-attachments/assets/8d426da1-5351-4240-a290-8d858be61312" />
Steps to Reproduce:
- Start Yamcs and login as a user
- Paste the following URL in the browser and press enter:
http://localhost:8090//etc/passwd
- The
/etc/passwdfile will be downloaded.
Acknowledgements
This vulnerability was discovered by Abderrahim Dahmani while solving a STARPWN 2025 CTF challenge at DEFCON 33 offered by VisionSpace Technologies.
- Record
GHSA-9jg3-g3wh-w9pj- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.yamcs:yamcs-coreMaven |
before 5.11.13 | 5.11.13 |
org.yamcs:yamcs-coreMaven |
before 5.12.0, plus listed versions 0.29.30.30.03.0.03.1.03.1.1 Show 45 moreShow less3.1.23.2.03.2.13.2.23.3.03.3.13.4.03.4.13.4.113.4.23.4.33.4.43.4.53.4.63.4.84.0.04.0.14.1.14.1.24.10.04.10.14.10.24.10.34.10.44.10.54.10.64.10.74.10.84.10.94.2.04.2.14.2.24.3.04.3.14.4.04.4.14.4.24.5.04.6.04.6.14.6.24.6.34.74.7.14.7.3 |
5.12.0 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Nuclei | Yamcs <=5.11.12 - Arbitrary File Read |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, Nuclei, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-55552 is a high vulnerability (CVSS 7.5) in Yamcs, published August 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.72%, the 77th percentile. Fixed in org.yamcs:yamcs-core 5.11.13.
References
github.com/yamcs/yamcs/security/advisories/GHSA-9jg3-g3wh-w9pj
nvd.nist.gov/vuln/detail/CVE-2026-55552
Left out here: 108 versions. The JSON record has them.