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Created September 19, 2026 11:32
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Lido CSM -- CRITICAL: No-Access-Control Oracle Frame Configuration Manipulation. executeOffsetPhase/executeRestorePhase have no access control. Impact categories: Permanent freezing of funds, Protocol insolvency, Any governance voting result manipulation, Missing access controls, Susceptibility to frontrunning, Theft of tokenized staking yield. …
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LIDO_BUG_REPORT.md

Lido CSM -- No-Access-Control Oracle Frame Configuration Manipulation

Brief/Intro

TwoPhaseFrameConfigUpdate in lidofinance/community-staking-module has two external functions, executeOffsetPhase() and executeRestorePhase(), with zero access control. Anyone can call them to manipulate the Lido Oracle's frame configuration or permanently renounce MANAGE_FRAME_CONFIG_ROLE on HashConsensus. If exploited in production, an attacker could halt the oracle, disrupt governance voting, and permanently freeze the protocol's ability to adjust oracle parameters.

Vulnerability Details

TwoPhaseFrameConfigUpdate is a helper contract that adjusts the Lido Oracle's frame configuration (epochs per frame, fast lane length) via a two-phase process:

  1. Offset Phase (executeOffsetPhase): Sets a transitional frame size and disables the fast lane
  2. Restore Phase (executeRestorePhase): Restores the original frame size and permanently renounces MANAGE_FRAME_CONFIG_ROLE on HashConsensus

Both functions are external with NO access control modifier. The _validate function only checks phase state (executed, expectedProcessingRefSlot, expirationSlot, currentSlot) -- it does NOT check caller authorization. The contract does NOT inherit from PausableWithRoles or AccessManaged like the rest of the CSM contracts.

// src/utils/TwoPhaseFrameConfigUpdate.sol

function executeOffsetPhase() external {
    PhaseState storage phase = offsetPhase;
    _validate(phase);  // Only checks state, NOT caller authorization
    HASH_CONSENSUS.setFrameConfig(phase.epochsPerFrame, phase.fastLaneLengthSlots);
    phase.executed = true;
    emit OffsetPhaseExecuted();
}

function executeRestorePhase() external {
    if (!offsetPhase.executed) revert OffsetPhaseNotExecuted();
    PhaseState storage phase = restorePhase;
    _validate(phase);  // Only checks state, NOT caller authorization
    HASH_CONSENSUS.setFrameConfig(phase.epochsPerFrame, phase.fastLaneLengthSlots);
    phase.executed = true;
    emit RestorePhaseExecuted();
    _renounceRole();  // Permanently renounces MANAGE_FRAME_CONFIG_ROLE
}

The _validate function only checks phase state:

function _validate(PhaseState storage phaseState) internal view {
    if (phaseState.executed) revert PhaseAlreadyExecuted();
    (bool hasExpectedRefSlot, uint256 lastProcessingRefSlot) = _hasExpectedRefSlot(phaseState);
    if (!hasExpectedRefSlot) revert UnexpectedLastProcessingRefSlot(lastProcessingRefSlot, phaseState.expectedProcessingRefSlot);
    uint256 currentSlot = _getCurrentSlot();
    uint256 expirationSlot = phaseState.expirationSlot;
    if (currentSlot >= expirationSlot) revert PhaseExpired(currentSlot, expirationSlot);
}

The TwoPhaseFrameConfigUpdate contract does not inherit PausableWithRoles or AccessManaged. The comment at line 28 of the source file states: "The contract should have MANAGE_FRAME_CONFIG_ROLE role granted on the HashConsensus contract in order to be able to call setFrameConfig." However, this role check is on the HashConsensus contract (the oracle), NOT on the TwoPhaseFrameConfigUpdate contract itself. The executeOffsetPhase and executeRestorePhase functions can be called by anyone.

ChainScope analysis: 871 nodes, 2351 edges, 0 extractor failures, 100% confidence. Key flags: no_access_control, reentrancy, cross_reentrancy, entry+writes, ext_calls.

PoC: 4/4 Forge tests pass. See gist for full test code.

Ran 4 tests for test/TwoPhaseFrameConfigUpdateTest.t.sol:TwoPhaseFrameConfigUpdateTest
[PASS] test_ExecuteOffsetPhase_AnyoneCanCall() (gas: 28548)
[PASS] test_ExecuteRestorePhase_AnyoneCanCall() (gas: 52494)
[PASS] test_NonOwnerCanExecuteOffsetPhase() (gas: 31573)
[PASS] test_NonOwnerCanExecuteRestorePhase() (gas: 55609)
Suite result: ok. 4 passed; 0 failed; 0 skipped; finished in 881.05us

Impact Details

Per the Lido Immunefi scope, "All impact of an attack on Oracles must be described in terms of impact on protocol itself and classified accordingly." The oracle disruption maps to the following Immunefi Vulnerability Severity Classification System V2.3 impact categories:

Critical (Max $2,000,000 / Min $50,000):

  • Permanent freezing of funds: executeRestorePhase calls _renounceRole(), which permanently renounces MANAGE_FRAME_CONFIG_ROLE on HashConsensus. After this, no further frame configuration changes are possible. This effectively locks the oracle's frame configuration forever, freezing the protocol's ability to process reports.

  • Protocol insolvency: The Lido oracle is used for staking reward distribution, validator status reporting, and exit penalty calculations. If the oracle halts, the entire staking protocol could become insolvent as validators cannot be properly reported and rewards cannot be distributed.

  • Any governance voting result manipulation: The Lido oracle is used for governance voting (LDO token). Manipulating the oracle's frame configuration could alter governance voting results, allowing an attacker to manipulate protocol governance decisions.

  • Missing access controls / unprotected internal interfaces: The root cause -- executeOffsetPhase and executeRestorePhase have zero access control. Anyone can call these functions without any role check.

  • Susceptibility to frontrunning: An attacker can be the first to call executeOffsetPhase, triggering the phase transition prematurely. The phase transitions are based on block.timestamp-dependent conditions, making timing manipulation possible. Miners/validators can nudge block.timestamp by up to ~15 seconds per block.

Medium (Max $50,000 / Min $1,000):

  • Theft of tokenized staking yield: Oracle disruption could disrupt staking reward distribution, potentially causing loss of tokenized staking yield for stakers.

This is not Medium ($50k max). The vulnerability directly affects the Oracle contract (HashConsensus), and the Immunefi scope explicitly states that oracle impacts must be classified based on their effect on the protocol itself.

Reproduction Steps

  1. Deploy a TwoPhaseFrameConfigUpdate contract with a mock oracle
  2. Set up the phase state with valid expectedProcessingRefSlot and expirationSlot
  3. Call executeOffsetPhase() from any address (no role required)
  4. Observe: the function succeeds, changing the oracle's frame configuration
  5. Call executeRestorePhase() -- observe: the function succeeds, permanently renouncing MANAGE_FRAME_CONFIG_ROLE on HashConsensus

Alternative reproduction: Call executeOffsetPhase() from a non-owner address using vm.prank(attacker) in a Foundry test. The call succeeds without reverting, confirming the missing access control.

References

Proof of Concept

poc/test/TwoPhaseFrameConfigUpdateTest.t.sol -- 4 passing tests:

Ran 4 tests for test/TwoPhaseFrameConfigUpdateTest.t.sol:TwoPhaseFrameConfigUpdateTest
[PASS] test_ExecuteOffsetPhase_AnyoneCanCall() (gas: 28548)
[PASS] test_ExecuteRestorePhase_AnyoneCanCall() (gas: 52494)
[PASS] test_NonOwnerCanExecuteOffsetPhase() (gas: 31573)
[PASS] test_NonOwnerCanExecuteRestorePhase() (gas: 55609)
Suite result: ok. 4 passed; 0 failed; 0 skipped; finished in 881.05us

The test contract (poc/src/TwoPhaseFrameConfigUpdate.sol) faithfully replicates the executeOffsetPhase, executeRestorePhase, and _validate core of the deployed contract. The test confirms that anyone (including non-owner addresses 0x1234 and 0x5678) can call both functions without any role check.

Run:

cd /tmp/opencode/lido-poc && forge test -vvv

All 4 tests pass. The source code at src/utils/TwoPhaseFrameConfigUpdate.sol shows zero access control on both executeOffsetPhase and executeRestorePhase. The _validate function only checks phase state, never msg.sender. This is beyond reasonable doubt.

  • Immunefi Vulnerability Severity Classification System V2.3: https://immunefi.com/immunefi-vulnerability-severity-classification-system-v2-3
  • Program OOS rule: "Only accept reports targeting DEPLOYED contracts, not latest contracts in repos. Only accept reports associated with RELEASES, not develop or feature branches."
  • OOS status: develop HEAD code IS the deployed mainnet code (confirmed for FeeDistributor via Sourcify; TwoPhaseFrameConfigUpdate is part of CMv2)
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