CVE-2026-34064

CVE-2026-34064 is a medium-severity vulnerability in Nimiq Nimiq Proof-of-stake with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-191.

Key facts

Description

nimiq-account contains account primitives to be used in Nimiq's Rust implementation. Prior to version 1.3.0, `VestingContract::can_change_balance` returns `AccountError::InsufficientFunds` when `new_balance < min_cap`, but it constructs the error using `balance: self.balance - min_cap`. `Coin::sub` panics on underflow, so if an attacker can reach a state where `min_cap > balance`, the node crashes while trying to return an error. The `min_cap > balance` precondition is attacker-reachable because the vesting contract creation data (32-byte format) allows encoding `total_amount` without validating `total_amount <= transaction.value` (the real contract balance). After creating such a vesting contract, the attacker can broadcast an outgoing transaction to trigger the panic during mempool admission and block processing. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available.

Frequently asked questions

What is CVE-2026-34064?
nimiq-account contains account primitives to be used in Nimiq's Rust implementation. Prior to version 1.3.0, `VestingContract::can_change_balance` returns `AccountError::InsufficientFunds` when `new_balance < min_cap`, but it constructs the error using `balance: self.balance - min_cap`. `Coin::sub` panics on underflow, so if an attacker can reach a state where `min_cap > balance`, the node crashes while trying to return an error. The `min_cap > balance` precondition is attacker-reachable because the vesting contract creation data (32-byte format) allows encoding `total_amount` without validating `total_amount <= transaction.value` (the real contract balance). After creating such a vesting contract, the attacker can broadcast an outgoing transaction to trigger the panic during mempool admission and block processing. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available.
How severe is CVE-2026-34064?
CVE-2026-34064 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-34064 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34064?
CVE-2026-34064 affects Nimiq Nimiq Proof-of-stake. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34064?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34064 have an EU (EUVD) identifier?
Yes. CVE-2026-34064 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25060.
When was CVE-2026-34064 published?
CVE-2026-34064 was published on 2026-04-22 and last updated on 2026-06-17.

References

Affected products (1)

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