CVE-2026-112112
CZ.NIC BIRD IPv6 FlowSpec Validation Bypass
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.
INFO
Published Date :
Oct. 18, 2026, 11:16 p.m.
Last Modified :
Oct. 18, 2026, 11:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | LOW | 8254265b-2729-46b6-b9e3-3dfca2d5bfca | ||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Verify unicast-route validation is correctly configured.
- Apply updates for BIRD Internet Routing Daemon.
- Implement RFC 8956 compliant filtering.
- Review BGP peer authorization settings.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-112112.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-112112 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-112112
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-112112 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-112112 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Oct. 18, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/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 Added CWE CWE-1284 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/112xxx/CVE-2026-112112.json">CVE-2026-112112</a> Added Reference https://gitlab.nic.cz/labs/bird/-/blob/v2.20.0/nest/rt-table.c#L2686 Added Reference https://gitlab.nic.cz/labs/bird/-/blob/v3.4.0/nest/rt-table.c#L4518 Added Reference https://gitlab.nic.cz/labs/bird/-/commit/7cf75587b6f38b87849fe192bf5dfd124b7702bc Added Reference https://www.rfc-editor.org/rfc/rfc8956.html#section-5