CVE-2026-11746

A vulnerability has been identified in centraldogma-server versions prior to 0.84.0, where enabling ZooKeeper replication without setting replication.secret causes the server to silently fall back to a hard-coded, publicly known secret. This default credential authenticates the embedded ZooKeeper ensemble, allowing an attacker with network access to read the full replication log or join the quorum and execute arbitrary replicated commands across the cluster.

A vulnerability has been identified in centraldogma-server versions prior to 0.84.0, where enabling ZooKeeper replication without setting replication.secret causes the server to silently fall back to a hard-coded, publicly known secret. This default credential authenticates the embedded ZooKeeper ensemble, allowing an attacker with network access to read the full replication log or join the quorum and execute arbitrary replicated commands across the cluster.

Vulnerability

ZooKeeperReplicationConfig.secret() silently substitutes the hard-coded constant "ch4n63m3" (leetspeak for "change me") whenever the operator omits replication.secret. The same secret is wired into both the client-facing SASL context and the quorum/learner SASL contexts of the embedded ZooKeeper. The constant is in OSS source on GitHub and is discoverable via code search in seconds.

Three Reinforcing Defects

1. OSS-public credential — DEFAULT_SECRET is in line/centraldogma source.
2. Silent fallback — firstNonNull(convertValue(...), DEFAULT_SECRET) substitutes the default with no log, no warning, no startup banner. The only sanity check checkArgument(!secret().isEmpty(), ...) passes because the getter substitutes the literal before the emptiness check runs.
3. Dual-purpose secret — used for both ZK client-port super auth and inter-peer quorum SASL. A single leaked password authenticates against both surfaces.

Architecture Context (Important)

Central Dogma does NOT connect to an external ZooKeeper ensemble. Each replica embeds a QuorumPeer (EmbeddedZooKeeper extends QuorumPeer) inside its own JVM. The Central Dogma cluster IS the ZK ensemble. So the "ZK network" is the inter-replica network of the Central Dogma cluster itself.

Applicability

| replication.method | ZK Started? | Applicable? | |---|---|---| | NONE (standalone, dev default) | No | NOT applicable | | ZOOKEEPER (HA production) | Yes, embedded on every replica | Fully applicable — canonical production configuration |

Evidence

File: server/src/main/java/com/linecorp/centraldogma/server/ZooKeeperReplicationConfig.java Branch: main @ commit d64a5151

Line 53 — the constant:

private static final String DEFAULT_SECRET = "ch4n63m3";

Lines 210–215 — the silent fallback:

/**
 * Returns the secret string used for authenticating the ZooKeeper peers.
 */
public String secret() {
    return firstNonNull(convertValue(secret, "replication.secret"), DEFAULT_SECRET);
}

File: server/src/main/java/com/linecorp/centraldogma/server/internal/replication/ZooKeeperCommandExecutor.java Lines 586–607 — JAAS wiring (same secret on both surfaces):

final String escapedSecret = jaasValueEscaper.escape(cfg.secret());
ImmutableList.of("Server", EmbeddedZooKeeper.SASL_SERVER_LOGIN_CONTEXT).forEach(name -> {
    buf.append(name).append(" {").append(newline);
    buf.append(DigestLoginModule.class.getName()).append(" required").append(newline);
    buf.append("user_super=\"").append(escapedSecret).append("\";").append(newline);
    buf.append("};").append(newline);
});
ImmutableList.of("Client", EmbeddedZooKeeper.SASL_LEARNER_LOGIN_CONTEXT).forEach(name -> {
    buf.append(name).append(" {").append(newline);
    buf.append(DigestLoginModule.class.getName()).append(" required").append(newline);
    buf.append("username=\"super\"").append(newline);
    buf.append("password=\"").append(escapedSecret).append("\";").append(newline);
    buf.append("};").append(newline);
});

File: server/src/main/java/com/linecorp/centraldogma/server/internal/replication/EmbeddedZooKeeper.java

Line 44 — proves CD embeds the ZK server:

final class EmbeddedZooKeeper extends QuorumPeer {

Lines 213–220 — client port binding (loopback only):

private static ServerCnxnFactory createCnxnFactory(QuorumPeerConfig zkCfg) throws IOException {
    final InetSocketAddress bindAddr = zkCfg.getClientPortAddress();
    final ServerCnxnFactory cnxnFactory = ServerCnxnFactory.createFactory();
    // Listen only on 127.0.0.1 because we do not want to expose ZooKeeper to others.
    cnxnFactory.configure(new InetSocketAddress("127.0.0.1", bindAddr != null ? bindAddr.getPort() : 0),
                          zkCfg.getMaxClientCnxns());
    return cnxnFactory;
}

Quorum/election ports are…

A vulnerability has been identified in centraldogma-server versions prior to 0.84.0, where enabling ZooKeeper replication without setting replication.secret causes the server to silently fall back to a hard-coded, publicly known secret. This default credential authenticates the embedded ZooKeeper ensemble, allowing an attacker with network access to read the full replication log or join the quorum and execute arbitrary replicated commands across the cluster.

A vulnerability has been identified in centraldogma-server versions prior to 0.84.0, where enabling ZooKeeper replication without setting replication.secret causes the server to silently fall back to a hard-coded, publicly known secret. This default credential authenticates the embedded ZooKeeper ensemble, allowing an attacker with network access to read the full replication log or join the quorum and execute arbitrary replicated commands across the cluster.

Vulnerability

ZooKeeperReplicationConfig.secret() silently substitutes the hard-coded constant "ch4n63m3" (leetspeak for "change me") whenever the operator omits replication.secret. The same secret is wired into both the client-facing SASL context and the quorum/learner SASL contexts of the embedded ZooKeeper. The constant is in OSS source on GitHub and is discoverable via code search in seconds.

Three Reinforcing Defects

1. OSS-public credential — DEFAULT_SECRET is in line/centraldogma source.
2. Silent fallback — firstNonNull(convertValue(...), DEFAULT_SECRET) substitutes the default with no log, no warning, no startup banner. The only sanity check checkArgument(!secret().isEmpty(), ...) passes because the getter substitutes the literal before the emptiness check runs.
3. Dual-purpose secret — used for both ZK client-port super auth and inter-peer quorum SASL. A single leaked password authenticates against both surfaces.

Architecture Context (Important)

Central Dogma does NOT connect to an external ZooKeeper ensemble. Each replica embeds a QuorumPeer (EmbeddedZooKeeper extends QuorumPeer) inside its own JVM. The Central Dogma cluster IS the ZK ensemble. So the "ZK network" is the inter-replica network of the Central Dogma cluster itself.

Applicability

| replication.method | ZK Started? | Applicable? | |---|---|---| | NONE (standalone, dev default) | No | NOT applicable | | ZOOKEEPER (HA production) | Yes, embedded on every replica | Fully applicable — canonical production configuration |

Evidence

File: server/src/main/java/com/linecorp/centraldogma/server/ZooKeeperReplicationConfig.java Branch: main @ commit d64a5151

Line 53 — the constant:

private static final String DEFAULT_SECRET = "ch4n63m3";

Lines 210–215 — the silent fallback:

/**
 * Returns the secret string used for authenticating the ZooKeeper peers.
 */
public String secret() {
    return firstNonNull(convertValue(secret, "replication.secret"), DEFAULT_SECRET);
}

File: server/src/main/java/com/linecorp/centraldogma/server/internal/replication/ZooKeeperCommandExecutor.java Lines 586–607 — JAAS wiring (same secret on both surfaces):

final String escapedSecret = jaasValueEscaper.escape(cfg.secret());
ImmutableList.of("Server", EmbeddedZooKeeper.SASL_SERVER_LOGIN_CONTEXT).forEach(name -> {
    buf.append(name).append(" {").append(newline);
    buf.append(DigestLoginModule.class.getName()).append(" required").append(newline);
    buf.append("user_super=\"").append(escapedSecret).append("\";").append(newline);
    buf.append("};").append(newline);
});
ImmutableList.of("Client", EmbeddedZooKeeper.SASL_LEARNER_LOGIN_CONTEXT).forEach(name -> {
    buf.append(name).append(" {").append(newline);
    buf.append(DigestLoginModule.class.getName()).append(" required").append(newline);
    buf.append("username=\"super\"").append(newline);
    buf.append("password=\"").append(escapedSecret).append("\";").append(newline);
    buf.append("};").append(newline);
});

File: server/src/main/java/com/linecorp/centraldogma/server/internal/replication/EmbeddedZooKeeper.java

Line 44 — proves CD embeds the ZK server:

final class EmbeddedZooKeeper extends QuorumPeer {

Lines 213–220 — client port binding (loopback only):

private static ServerCnxnFactory createCnxnFactory(QuorumPeerConfig zkCfg) throws IOException {
    final InetSocketAddress bindAddr = zkCfg.getClientPortAddress();
    final ServerCnxnFactory cnxnFactory = ServerCnxnFactory.createFactory();
    // Listen only on 127.0.0.1 because we do not want to expose ZooKeeper to others.
    cnxnFactory.configure(new InetSocketAddress("127.0.0.1", bindAddr != null ? bindAddr.getPort() : 0),
                          zkCfg.getMaxClientCnxns());
    return cnxnFactory;
}

Quorum/election ports are…