CVE-2026-53499: FORT-validator Vulnerable to RRDP Shared Snapshot Cache Poisoning
FORT Validator is a Resource Public Key Infrastructure (RPKI) relying-party validator that produces validated route-origin data. FORT Validator versions through 1.6.7 contain an origin-validation error in their RRDP processing: a delegated CA under the same Trust Anchor Locator (TAL) can reference a victim CA’s public RRDP notification and snapshot URLs, causing FORT’s URL-based download cache to report success after deleting the victim’s local snapshot. Following a routine victim publication, this can silently remove the victim’s VRPs and other signed objects from FORT’s output, potentially enabling route hijacking or loss of reachability. Version 1.6.8 contains a patch that rejects cross-origin RRDP snapshot and delta URLs; as a workaround, administrators can disable HTTP/RRDP with --http.enabled=false while keeping rsync enabled, although this can leave data unavailable or stale where rsync is not supported.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
FORT Validatorto a version that resolves this vulnerability.Fixed in 1.6.8 - Configuration
As a workaround, disable HTTP/RRDP by setting --http.enabled=false while keeping rsync enabled.
FORT Validator --http.enabled = false
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
FORT Validator deployments running version 1.6.7 or earlier are affected when they process RRDP content. A delegated CA under the same Trust Anchor Locator must be able to reference another CA's RRDP notification and snapshot URLs.
What is the operational impact of successful exploitation?
The victim CA's local snapshot can be deleted while the download cache reports success. After the victim's normal publication, its VRPs and other signed objects may disappear from FORT output, potentially allowing route hijacking or causing reachability loss.
What should administrators do if they cannot immediately upgrade?
Disable HTTP/RRDP processing with --http.enabled=false and continue using rsync. This workaround may leave data unavailable or stale for repositories that do not support rsync.
How is the issue fixed?
Upgrade to FORT Validator 1.6.8, which rejects RRDP snapshot and delta URLs that cross origins.