CVE-2026-129456
Received
Received - Intake
Memory Corruption in FRRouting bgpd via BGP Tunnel Encapsulation
Vulnerability report for CVE-2026-129456, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-14
Last updated on: 2026-11-14
Assigner: 57a55968-44ac-464c-a794-6ba3baad09c4
Description
Description
In FRRouting, bgpd accepts a Tunnel Encapsulation attribute (type 23) whose outer TLV length does not match the length of the attribute: the mismatch is only logged and the attribute is processed anyway. A BGP neighbor can send UPDATE messages carrying such an attribute that put the reference count of the attribute's interned sub-TLV chain out of balance, so that the chain is freed while routes stored by bgpd (Adj-RIB-In entries and RIB paths) still point to it. When those routes are later replaced, withdrawn or cleared, for example when the session goes down, bgpd reads the freed memory, decrements a reference count inside it and frees it a second time. In the reporter's build without AddressSanitizer this ended in an assertion failure in bgpd's memory accounting, aborting bgpd and dropping all BGP sessions on the router, and the neighbor can repeat it each time bgpd restarts. Because freed heap memory is written to and freed again, consequences beyond a crash cannot be ruled out. An established BGP session is required. bgpd processes attribute 23 from every neighbor, including eBGP neighbors, unless it is explicitly discarded, although RFC 9012 requires it to be filtered on eBGP sessions by default. The issue was reproduced with "soft-reconfiguration inbound" configured for the neighbor, and the reporter observed that the crash does not occur on every attempt.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
| CWE-415 | The product calls free() twice on the same memory address. |
