nimiq-blockchain is missing a wall-clock upper bound on block timestamps

CVE-2026-40093 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Impact

Block timestamp validation enforces that timestamp >= parent.timestamp for non-skip blocks and timestamp == parent.timestamp + MIN_PRODUCER_TIMEOUT for skip blocks, but there is no visible upper bound check against the wall clock. A malicious block-producing validator can set block timestamps arbitrarily far in the future. This directly affects reward calculations via Policy::supply_at() and batch_delay() in blockchain/src/reward.rs, inflating the monetary supply beyond the intended emission schedule.

Patches

TBD

Workarounds

No know workarounds.

Basic information

Type
reviewed
Severity
critical
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Browse source ↗
Published (advisory)
2026-04-10 19:55:04 UTC
Updated
2026-04-14 10:39:36 UTC
GitHub reviewed
2026-04-10 19:55:04 UTC
NVD published
2026-04-09

EPSS Score

Score Percentile
0.07% 20.34%

CVSS Scores

Base score Version Severity Vector
9.1 3.1 —
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-49xc-52mp-cc9j ↗
CVE CVE-2026-40093 ↗

CWEs

CWE id Name
CWE-20 Improper Input Validation
CWE-1284 Improper Validation of Specified Quantity in Input

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
rust nimiq-blockchain <= 1.3.0 — —

References

cvelogic Threat Intelligence