Vulnerability · Published Aug 21, 2026 · Assigned by GitHub_M

CVE-2026-53499FORT-validator Vulnerable to RRDP Shared Snapshot Cache Poisoning

High 7.2

In plain English

A high-severity security flaw in FORT-validator from NICMx. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.2High

Exploit odds (30 days)0.2%top 90.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	fort-validator	no fix listed	DEBIAN-CVE-2026-53499
Debian:13	fort-validator	1.6.8-0+deb13u1	DEBIAN-CVE-2026-53499
Debian:14	fort-validator	1.6.8-1	DEBIAN-CVE-2026-53499
Ubuntu:22.04:LTS	fort-validator	no fix listed	UBUNTU-CVE-2026-53499
Ubuntu:26.04:LTS	fort-validator	no fix listed	UBUNTU-CVE-2026-53499

Affected products (as reported)

Vendor	Product	Versions
NICMx	FORT-validator	< 1.6.8

Weakness: CWE-346 · 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

References

https://github.com/NICMx/FORT-validator/security/advisories/GHSA-qfm3-577x-rh54 x_refsource_CONFIRM