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

This month

HIGH 7.5REMOTEDOWNGRADE

CVE-2024-56375 is a high-severity flaw (CVSS 7.5) affecting fort validator. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 59%)
CISA exploited list	No
Weakness	CWE-191
Published	2024-12-22
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: nicmx

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2024-12-22 23:15 UTCPublished CVE record published
2026-06-17 08:12 UTCUpdated Record last modified

nicmx fort validator DOWNGRADE

Affected: 1.6.3 · 1.6.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.6.3

1. Check installed version

apt-cache policy fort-validator || rpm -q fort-validator || fort-validator --version

2. No fixed release: DOWNGRADE to a release before 1.6.3 (Debian / Ubuntu)

apt-cache madison fort-validator sudo apt install fort-validator=<VERSION_BEFORE_1.6.3> sudo apt-mark hold fort-validator

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list fort-validator sudo dnf downgrade fort-validator-<VERSION_BEFORE_1.6.3> sudo dnf versionlock add fort-validator

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2024-56375?

fort validator: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2024-56375 being exploited?

CVE-2024-56375 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2024-56375 affect?

CVE-2024-56375 affects fort validator. Severity is high (CVSS 7.5). 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 derefe

How urgent is CVE-2024-56375?

Priority 41/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2024-56169 MEDIUM 5.3 UPGRADE A validation integrity issue was discovered in Fort through 1.6.4 before 2.0.0
CVE-2024-45238 HIGH 7.5 UPGRADE An issue was discovered in Fort before 1.6.3
CVE-2024-45235 HIGH 7.5 UPGRADE An issue was discovered in Fort before 1.6.3

References

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