rust-lang/cargo · error

error: Found a `@cert-authority` marker for

Error message

error: Found a `@cert-authority` marker for `{hostname}`

Cargo doesn't support certificate authorities for host key verification. It is
recommended that the command line Git client is used instead. This can be achieved
by setting `net.git-fetch-with-cli` to `true` in the Cargo config.

The `@cert-authority` line was found in {location}.

See https://doc.rust-lang.org/stable/cargo/appendix/git-authentication.html#ssh-known-hosts for more information.

What it means

Error "error: Found a `@cert-authority` marker for `{hostname}` Cargo doesn't support certificate authorities for host key verification. It is recommended that the command line Git client is used instead. This can be achieved by setting `net.git-fetch-with-cli` to `true` in the Cargo config. The `@cert-authority` line was found in {location}. See https://doc.rust-lang.org/stable/cargo/appendix/git-authentication.html#ssh-known-hosts for more information. " thrown in rust-lang/cargo.

When it happens

Trigger: Thrown at src/sources/git/known_hosts.rs:312 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• SSL/TLS and certificate errors — how TLS handshakes and certificate validation fail.
• Authentication and authorization failures — expired tokens, bad credentials, and missing scopes.

AI-assisted analysis of rust-lang/cargo@eb98b54bc9 (2026-08-11). Data as JSON: /api/errors/44824c48b7627685. Report an issue: GitHub.

Appendix: source

Thrown at src/sources/git/known_hosts.rs:312

            remote_host_key,
            location,
        }) => {
            let key_type_short_name = key_type.short_name();
            anyhow::bail!(
                "error: Key has been revoked for `{hostname}`\n\
                **************************************\n\
                * WARNING: REVOKED HOST KEY DETECTED *\n\
                **************************************\n\
                This may indicate that the key provided by this host has been\n\
                compromised and should not be accepted.
                \n\
                The host key {key_type_short_name} {remote_host_key} is revoked\n\
                in {location} and has been rejected.\n\
                "
            )
        }
        Err(KnownHostError::HostHasOnlyCertAuthority { hostname, location }) => {
            anyhow::bail!("error: Found a `@cert-authority` marker for `{hostname}`\n\
                \n\
                Cargo doesn't support certificate authorities for host key verification. It is\n\
                recommended that the command line Git client is used instead. This can be achieved\n\
                by setting `net.git-fetch-with-cli` to `true` in the Cargo config.\n\
                \n
                The `@cert-authority` line was found in {location}.\n\
                \n\
                See https://doc.rust-lang.org/stable/cargo/appendix/git-authentication.html#ssh-known-hosts \
                for more information.\n\
                ")
        }
    }
}

/// Checks if the given host/host key pair is known.
fn check_ssh_known_hosts(
    gctx: &GlobalContext,
    cert_host_key: &git2::cert::CertHostkey<'_>,

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