CVE-2026-112112

Description

An IPv6 FlowSpec validation bypass in the CZ.NIC BIRD Internet Routing Daemon allows an established BGP peer to inject FlowSpec rules matching destinations outside the address space authorized by the unicast-route validation procedure. With validation enabled on the receiving flow6 channel, BIRD fails to reject a destination prefix component with a nonzero offset, contrary to RFC 8956 section 5. It validates a reconstructed prefix with zero-filled skipped bits, although the original FlowSpec component can match a broader set of IPv6 addresses. Given a suitable unicast route from the peer, the rule can pass validation and, where export policy permits, be propagated to downstream peers. Downstream enforcement may cause unauthorized traffic filtering or redirection.

Is your site exposed to CVE-2026-112112?

Run a free security scan — no signup, results in seconds.

Weakness Type (CWE)

CWE-1284 CWE-1284

References

Other References

https://gitlab.nic.cz/labs/bird/-/blob/v2.20.0/nest/rt-table.c#L2686 https://gitlab.nic.cz/labs/bird/-/blob/v3.4.0/nest/rt-table.c#L4518 https://gitlab.nic.cz/labs/bird/-/commit/7cf75587b6f38b87849fe192bf5dfd124b7702bc https://www.rfc-editor.org/rfc/rfc8956.html#section-5

Frequently Asked Questions

What is CVE-2026-112112? +

An IPv6 FlowSpec validation bypass in the CZ.NIC BIRD Internet Routing Daemon allows an established BGP peer to inject FlowSpec rules matching destinations outside the address space authorized by the unicast-route validation procedure. With validation enabled on the receiving flow6 channel, BIRD fails to reject a destination prefix component with a nonzero offset, contrary to RFC 8956 section 5. It validates a reconstructed prefix with zero-filled skipped bits, although the original FlowSpec component can match a broader set of IPv6 addresses. Given a suitable unicast route from the peer, the rule can pass validation and, where export policy permits, be propagated to downstream peers. Downstream enforcement may cause unauthorized traffic filtering or redirection.

How do I check if I'm vulnerable to CVE-2026-112112? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-12974

A Security Policy Bypass vulnerability exists in Forcepoint Security Engine (NGFW). This issue affects Forcepoint Security Engine (NGFW): from 7.1.0 …

CVE-2025-41100

Incorrect authentication vulnerability in ParkingDoor. Through this vulnerability it is possible to operate the device without the access being logged …

CVE-2024-6768

A Denial of Service in CLFS.sys in Microsoft Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, and Windows …

CVE-2025-8424

Improper access control on the NetScaler Management Interface in NetScaler ADC and NetScaler Gateway when an attacker can get access …

CVE-2025-5808

Improper Input Validation vulnerability in OpenText Self Service Password Reset allows Authentication Bypass.This issue affects Self Service Password Reset from …

CVE-2025-9316

N-central < 2025.4 can generate sessionIDs for unauthenticated users This issue affects N-central: before 2025.4.