CVE-2026-111062Eugeny russh improper signature verification
CVE-2026-111062 is a improper signature verification in Eugeny russh, rated low (2.3 on CVSS 4.0).
Why this priority: Low severity, with no exploitation signal.
Published · Updated · NVD status: Deferred
What it is
A cryptographic signature is not checked properly, so forged data is accepted.
How it is reached
An attacker can exploit it over the network, with an ordinary user account, and nobody has to click anything. Success also depends on conditions the attacker does not fully control.
What an attacker gains
The direct impact is limited: partial access to data or a partial outage. In practice, this kind of flaw lets an attacker read or tamper with traffic, or pass a forged message as genuine.
Is it being exploited?
CISA's SSVC assessment notes a public proof of concept.
What to do
- Upgrade Eugeny russh to 0.64.0 or later.
- Until it is patched, review who holds accounts that can reach it.
Description from NVD
russh is a Rust SSH client and server library. From version 0.34.0-beta.1 until version 0.64.0, its SSH server does not require the signature algorithm in a public-key authentication signature to match the algorithm named in the authentication request. A client possessing an authorized RSA private key can announce rsa-sha2-512 while supplying a valid ssh-rsa SHA-1 signature, bypassing restrictions or producing misleading audit records when applications rely on the requested algorithm. A valid private-key signature remains required, and russh clients are not affected. This issue is fixed in version 0.64.0.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- TLS termination and service-to-service channels. The flaw sits on the network path between clients and services.
- Signature checks. The flaw sits on the network path between clients and services.
Trust boundaries in play
- Authenticated network access. An account is needed, so exposure follows who can sign in: customers, partners or staff.
- On the network path between clients and services. An attacker who crosses it can read or tamper with traffic, or pass a forged message as genuine.
Questions to answer about your own systems
- Where does Eugeny russh run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.