CVE-2026-12707: CWE-770 Allocation of resources without limits or throttling in Cloudflare quiche
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.
AI Analysis
Technical Summary
Cloudflare quiche is vulnerable to resource exhaustion due to unbounded queuing of PathEvent::ReusedSourceConnectionId events triggered by rapid source address migration after the QUIC handshake completes. Although quiche implements RFC 9000 Section 9.3 protections to limit server state, the collection of PathEvents was not bounded, allowing a peer to cause memory exhaustion. This affects versions from 0.15.0 up to but not including 0.29.3. The vulnerability can be mitigated by upgrading to quiche 0.29.3 or later or by applications actively draining the PathEvent queue via path_event_next().
Potential Impact
An attacker can cause memory resource exhaustion on servers running vulnerable versions of quiche by rapidly migrating the source address, leading to unbounded queuing of specific PathEvents. This results in a denial of service condition due to excessive memory consumption. The vulnerability does not impact confidentiality or integrity but affects availability.
Mitigation Recommendations
A fix is available in quiche version 0.29.3, which prevents excessive queuing of PathEvent::ReusedSourceConnectionId. Users should upgrade to version 0.29.3 or later. Alternatively, applications can mitigate the issue by calling path_event_next() to drain the PathEvent collection, reducing the risk of resource exhaustion.
CVE-2026-12707: CWE-770 Allocation of resources without limits or throttling in Cloudflare quiche
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.
CVSS v3.1
Score 7.5high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Cloudflare quiche is vulnerable to resource exhaustion due to unbounded queuing of PathEvent::ReusedSourceConnectionId events triggered by rapid source address migration after the QUIC handshake completes. Although quiche implements RFC 9000 Section 9.3 protections to limit server state, the collection of PathEvents was not bounded, allowing a peer to cause memory exhaustion. This affects versions from 0.15.0 up to but not including 0.29.3. The vulnerability can be mitigated by upgrading to quiche 0.29.3 or later or by applications actively draining the PathEvent queue via path_event_next().
Potential Impact
An attacker can cause memory resource exhaustion on servers running vulnerable versions of quiche by rapidly migrating the source address, leading to unbounded queuing of specific PathEvents. This results in a denial of service condition due to excessive memory consumption. The vulnerability does not impact confidentiality or integrity but affects availability.
Mitigation Recommendations
A fix is available in quiche version 0.29.3, which prevents excessive queuing of PathEvent::ReusedSourceConnectionId. Users should upgrade to version 0.29.3 or later. Alternatively, applications can mitigate the issue by calling path_event_next() to drain the PathEvent collection, reducing the risk of resource exhaustion.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cloudflare
- Date Reserved
- 2026-06-19T10:27:48.087Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Is Cloud Service
- true
Threat ID: 6a565a3968715ace43c7b5b9
Added to database: 07/14/2026, 15:48:09 UTC
Last enriched: 07/14/2026, 16:18:17 UTC
Last updated: 07/14/2026, 21:37:08 UTC
Views: 3
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