CVE-2026-12707
Unbounded path event queue growth in quiche via peer-driven source connection ID rotation
Description
Summary Cloudflare quiche was discovered to be vulnerable to memory resource exhaustion due to unbounded queuing of post-handshake client migration events. Impact quiche supports the connection migration features described in Section 9 of RFC 9000, which allows a single QUIC connection to survive changes in the network path. Although quiche implements the protections described in Section 9.3 of RFC 9000 to limit server state commitment, it was discovered that the collection of PathEvents, intended to be consumed by applications via the path_event_next() function, was not bounded. Once the QUIC handshake completed, a peer could exploit rapid source address migration in order to cause unbounded queuing of the PathEvent::ReusedSourceConnectionId type. Servers are vulnerable even if active connection migration is disabled. Mitigation: * Applications can call path_event_next() to drain the PathEvent collection, mitigating the attack. * Users are requested to upgrade to quiche 0.29.3 which is the earliest version that prevents excessive queueing of PathEvent::ReusedSourceConnectionId.
INFO
Published Date :
July 14, 2026, 4:16 p.m.
Last Modified :
Oct. 24, 2026, 9:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | a22f1246-ba21-4bb4-a601-ad51614c1513 | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Upgrade quiche to version 0.29.3 or newer.
- Call path_event_next() to drain PathEvent collection.
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-2026-12707.
| URL | Resource |
|---|---|
| https://github.com/cloudflare/quiche/security/advisories/GHSA-4q5x-gp38-rfp4 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-12707 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-2026-12707
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-2026-12707 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-12707 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.
-
CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Added Translation Title: quiche de Cloudflare, Description: Resumen Se descubrió que Cloudflare quiche era vulnerable al agotamiento de recursos de memoria debido al encolamiento ilimitado de eventos de migración de cliente post-handshake. Impacto quiche es compatible con las características de migración de conexión descritas en la Sección 9 de RFC 9000, lo que permite que una única conexión QUIC sobreviva a los cambios en la ruta de red. Aunque quiche implementa las protecciones descritas en la Sección 9.3 de RFC 9000 para limitar el compromiso de estado del servidor, se descubrió que la colección de PathEvents, destinada a ser consumida por las aplicaciones a través de la función path_event_next(), no estaba limitada. Una vez completado el handshake QUIC, un par podría explotar una rápida migración de dirección de origen para causar un encolamiento ilimitado del tipo PathEvent::ReusedSourceConnectionId. Los servidores son vulnerables incluso si la migración de conexión activa está deshabilitada. Mitigación: * Las aplicaciones pueden llamar a path_event_next() para vaciar la colección PathEvent, mitigando el ataque. * Se solicita a los usuarios que actualicen a quiche 0.29.3, que es la versión más temprana que previene el encolamiento excesivo de PathEvent::ReusedSourceConnectionId. -
New CVE Received by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/cloudflare/quiche', 'vendor': 'Cloudflare', 'product': 'quiche', 'versions': [{'status': 'affected', 'version': '0.15.0', 'lessThan': '0.29.3', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] Added Description Summary Cloudflare quiche was discovered to be vulnerable to memory resource exhaustion due to unbounded queuing of post-handshake client migration events. Impact quiche supports the connection migration features described in Section 9 of RFC 9000, which allows a single QUIC connection to survive changes in the network path. Although quiche implements the protections described in Section 9.3 of RFC 9000 to limit server state commitment, it was discovered that the collection of PathEvents, intended to be consumed by applications via the path_event_next() function, was not bounded. Once the QUIC handshake completed, a peer could exploit rapid source address migration in order to cause unbounded queuing of the PathEvent::ReusedSourceConnectionId type. Servers are vulnerable even if active connection migration is disabled. Mitigation: * Applications can call path_event_next() to drain the PathEvent collection, mitigating the attack. * Users are requested to upgrade to quiche 0.29.3 which is the earliest version that prevents excessive queueing of PathEvent::ReusedSourceConnectionId. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-770 Added Reference https://github.com/cloudflare/quiche/security/advisories/GHSA-4q5x-gp38-rfp4 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 14, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-12707', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-14T15:57:40.409163Z'}