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CVE-2026-53499NVD status: Deferred

FORT-validator: Origin Validation Error

CVE-2026-53499 is a high-severity origin validation error vulnerability in FORT-validator from Nicmx, with a CVSS 4.0 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected FORT-validator versions: < 1.6.8. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of FORT-validator you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
NICMxFORT-validator< 1.6.8Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
PresentThe target must be in a specific state or configuration for the attack to work.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
NoneNo loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
LowLimited loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
HighSerious loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
HighSerious loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (github.com).

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Origin Validation Error

The product does not properly verify that the source of data or communication is valid.

More Origin Validation Error vulnerabilities (CWE-346)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in FORT-validator

All FORT-validator vulnerabilities

Recent Origin Validation Error vulnerabilities

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