CVE-2026-47731 NASA AMMOS Instrument Toolkit: Path traversal resulting in arbitrary file append (can be triggered over the network by unauthenticated attacker)

What is CVE-2026-47731?

CVE-2026-47731 is a critical path traversal vulnerability in NASA-AMMOS AIT-Core, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

The AMMOS Instrument Toolkit (Formerly the Bespoke Links to Instruments for Surface and Space (BLISS)) is a Python-based software suite developed to handle Ground Data System (GDS), Electronic Ground Support Equipment (EGSE), commanding, telemetry uplink/downlink, and sequencing for instrument and CubeSat Missions. In versions prior to 2.6.1 and in version 3.1.0, the Binary Stream Capture (BSC) component exposes an unauthenticated HTTP API for dynamically creating packet capture "handlers." Because the code blindly trusts path‑related form fields, a remote client can bypass the configured log root and direct BSC to log to arbitrary filesystem paths (path traversal / directory escape), and append attacker‑controlled data to those files, using the privileges of the`ait-bsc` process. There are two ways for a remote attacker to trigger this. First, if the attacker has access to the network where `ait-bsc` is deployed (a reason for that could be that the ports are publicly accessible), the payloads can be directly sent to the server to trigger the arbitrary file append. This type of attack is demonstrated in `python_poc.py`. Second, even if the attacker does not have direct access to the network because the software is running in a local network, it is possible to exploit this if a bad actor in that network opens an attacker-controlled website (which might be a website created by an attacker, or a third-party website compromised by the attacker). The browser javascript can automatically send the requests necessary to exploit this into the local network. This is even possible if the server is only accessible on `localhost`. This type of attack is demonstrated by `attacker_tcp.py` and `test1.html` (first launch the attacker TCP server, then start a webserver to host `test1.html`, for example using `python3 -m http.server 7000`, and open `test1.html`).This issue affects BSC (Binary Stream Capture) and usage of the ait-bsc server. This impacts AIT-Core versions before 3.1.1, from 2.x before 2.6.1. Users are recommended to upgrade to version 3.1.1 or 2.6.1.

Weakness: CWE-22

Which versions are affected by CVE-2026-47731?

5 open source packages ship an affected version, including ait-core.

How do I fix CVE-2026-47731?

Upgrade ait-core to a fixed version for your release line: 2.6.1 or 3.1.1.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2026-47731 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-47731 exists.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-p462-prxw-mjx4, PYSEC-2026-265.