CVE-2026-30960: RSSN has Arbitrary Code Execution via Unvalidated JIT Instruction Generation in C-FFI Interface

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.2%, percentile 10: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 10% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
• Only applies if your dependency tree includes rssn (crates.io (Rust)) < 0.2.9, fixed in 0.2.9. Check your lockfile, including transitive dependencies.

What it is

rssn is a scientific computing library for Rust, combining a high-performance symbolic computation engine with numerical methods support and physics simulations functionalities. The vulnerability exists in the JIT (Just-In-Time) compilation engine, which is fully exposed via the CFFI (Foreign Function Interface). Due to Improper Input Validation and External Control of Code Generation, an attacker can supply malicious parameters or instruction sequences through the CFFI layer. Since the library often operates with elevated privileges or within high-performance computing contexts, this allows for Arbitrary Code Execution (ACE) at the privilege level of the host process.

From the GitHub advisory

Impact

Vulnerability Type: Improper Control of Generation of Code ('Code Injection') (CWE-94) / Improper Check for Unusual or Exceptional Conditions (CWE-754) / Improper Input Validation (CWE-20) / Use of Low-Level Functionality (CWE-695) / Improper Privilege Management (CWE-269) / External Control of System or Configuration Setting (CWE-15).

Technical Details: The vulnerability exists in the JIT (Just-In-Time) compilation engine, which is fully exposed via the CFFI (Foreign Function Interface). Due to Improper Input Validation and External Control of Code Generation, an attacker can supply malicious parameters or instruction sequences through the CFFI layer. Since the library often operates with elevated privileges or within high-performance computing contexts, this allows for Arbitrary Code Execution (ACE) at the privilege level of the host process.

Who is Impacted?

Developers using the library as a dynamic linked library (.so, .dll, .dylib) in multi-language environments (e.g., Python, Node.js, C++). Cloud Service Providers running the library in multi-tenant environments or automated model-training pipelines. Users processing untrusted or third-party datasets/models that may trigger malicious JIT instruction generation. Patches Affected versions:

Weakness type: CWE-94, CWE-269, CWE-695, CWE-754, CWE-15.

Product: rssn (crates.io (Rust)) · Assigned by: GitHub_M · Published: 2026-03-10

Affected and fixed versions

Severity scores

• Attack vector: local access needed
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.20% probability of exploitation activity in the next 30 days; percentile 10.

Timeline

• 2026-03-10 — CVE record last updated
• 2026-03-10 — CVE record published by GitHub_M
• 2026-03-10 — GitHub-reviewed advisory GHSA-9c4h-pwmf-m6fj published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-9c4h-pwmf-m6fj github.com
2. CVE.org record CVE-2026-30960 cve.org
3. NVD entry CVE-2026-30960 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. rustsec.org rustsec.org

Critical crates.io (Rust) advisories · Today’s Security Digest