CVE-2026-127122

Out-of-bounds write with too many MCR blocks in a Connect request

Published Nov 13, 2026 CVSS 4.0 · 7.2 High EPSS n/a KEV · Not listed
Description
P-Net before 1.0.4 does not check the number of MCR request blocks in a Connect request against the number of multicast communication relations that an Application Relationship has room for (PNET_MAX_MC_CR, 1 by default). Each further block is written past the end of the array, into the rest of the Application Relationship and, with more blocks, into the following one. The written data comes from the request. No established Application Relationship is needed, and the attacker requires ADJACENT network access. Builds with PNET_OPTION_MC_CR disabled are not affected.

Remediation

Vendor Solution

Upgrade to P-Net 1.0.4 or later.


Vendor Workaround

Build P-Net with PNET_OPTION_MC_CR disabled. Multicast communication relations are not supported by P-Net, and a Connect request with MCR blocks is then rejected.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description P-Net before 1.0.4 does not check the number of MCR request blocks in a Connect request against the number of multicast communication relations that an Application Relationship has room for (PNET_MAX_MC_CR, 1 by default). Each further block is written past the end of the array, into the rest of the Application Relationship and, with more blocks, into the following one. The written data comes from the request. No established Application Relationship is needed, and the attacker requires ADJACENT network access. Builds with PNET_OPTION_MC_CR disabled are not affected.
Title Out-of-bounds write with too many MCR blocks in a Connect request
Weaknesses CWE-787
References
Metrics cvssV4_0

{'score': 7.2, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N'}

Subscriptions

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Weaknesses

Sources

Status
PUBLISHED
Assigner
rt-labs
Published
Updated
Nov 13, 2026, 1:24 PM
Reserved
Nov 12, 2026, 3:30 PM
Status
Deferred
Published
Nov 13, 2026, 2:17 PM
Modified
Nov 13, 2026, 2:17 PM