CVE-2026-46673

Russh: Unchecked CryptoVec allocation and growth handling is reachable

This is a memory-safety hardening issue with demonstrated untrusted-input reachability.

What is demonstrated:

• current local agent peers could previously reach allocation growth directly from attacker-controlled frame lengths
• historical remote SSH traffic could previously reach CryptoVec through transport and compression buffers in russh < 0.58.0
• under constrained memory, the historical remote compression path can be turned into a process abort in the old Unix CryptoVec code
• the fixed code now rejects oversized agent frames early and hardens the underlying allocation paths

What is not demonstrated:

• practical code execution
• a demonstrated integrity or confidentiality break

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

CVE-2026-46673 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.60.3); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-46673? CVE-2026-46673 is a high-severity allocation of resources without limits or throttling vulnerability in russh-cryptovec (rust), affecting versions <= 0.60.2. It is fixed in 0.60.3. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. How severe is CVE-2026-46673? CVE-2026-46673 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-46673?
   • russh-cryptovec (rust) (versions <= 0.60.2)
   • russh (rust) (versions <= 0.60.2)
4. Is there a fix for CVE-2026-46673? Yes. CVE-2026-46673 is fixed in 0.60.3. Upgrade to this version or later.
5. Is CVE-2026-46673 exploitable, and should I be worried? Whether CVE-2026-46673 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-46673 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-46673?
   • Upgrade russh-cryptovec to 0.60.3 or later
   • Upgrade russh to 0.60.3 or later