When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them.
Weakness
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Crypto | Golang | * | 0.52.0 (excluding) |
| Golang-go.crypto | Ubuntu | esm-apps/focal | * |
| Golang-go.crypto | Ubuntu | esm-apps/jammy | * |
| Golang-go.crypto | Ubuntu | esm-apps/noble | * |
| Golang-go.crypto | Ubuntu | esm-apps/resolute | * |
| Golang-go.crypto | Ubuntu | jammy | * |
| Golang-go.crypto | Ubuntu | noble | * |
| Golang-go.crypto | Ubuntu | questing | * |
| Golang-go.crypto | Ubuntu | resolute | * |
| Golang-go.crypto | Ubuntu | upstream | * |
| Lxd | Ubuntu | esm-infra-legacy/xenial | * |
| Lxd | Ubuntu | esm-infra/bionic | * |
Potential Mitigations
- Make fields transient to protect them from deserialization.
- An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.