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Firewall Bypass in QNAP QHora-322 IPv6 PPPoE Rule Matching

IdentifiersCVE-2025-62843CWE-923· Improper Restriction of…

CVE-2025-62843 is an improper restriction of communication channel to intended endpoints vulnerability affecting QNAP QHora devices, including the QHora-322. Public reporting indicates the flaw is in the implementation of firewall rules, specifically a failure to correctly match IPv6 firewall rules on PPPoE connections. As a result, traffic can reach endpoints that should have been blocked by the configured firewall policy. Although one vendor description references physical access as an attack condition, the more specific disclosure states the issue is exploitable by a network-adjacent attacker without authentication. The vulnerability was disclosed through Pwn2Own and assigned ZDI-26-237 / ZDI-CAN-28371.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

A successful exploit allows an attacker to bypass firewall restrictions on affected QNAP QHora-322 installations. This can expose services or communication paths that administrators intended to block, reducing network segmentation and access-control effectiveness. The disclosed impact is limited direct compromise of confidentiality, integrity, and availability, but the flaw is significant because it can be chained with other vulnerabilities to achieve arbitrary code execution as root.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by limiting network-adjacent access to the router, especially over IPv6 and PPPoE-connected paths; restrict management and reachable services to trusted networks only; review firewall policy behavior for IPv6 traffic; and monitor for unexpected inbound or lateral traffic that may indicate firewall bypass. These are compensating controls only and do not replace upgrading to a fixed QuRouter release.

Remediation

Patch, then assume compromise.

Upgrade affected devices to QuRouter 2.6.3.009 or later. QNAP states the vulnerability has been fixed in that version line and published remediation guidance in security advisory QSA-26-12.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
QNAP SystemsQrouteroperating_system
QNAP SystemsQurouterapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

3 SOURCESView more in app
What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2025-62843
NVD
nvd.nist.gov/vuln/detail/CVE-2025-62843
MITRE CWE · CWE-923
Improper Restriction of Communication Channel…
Vendor Advisory
qnap.com/en/security-advisory/qsa-26-12