TI-2026-10866 Aliases CVE-2026-12707

Unbounded path event queue growth in quiche via peer-driven source connection ID rotation

LOW 39CWE-770Published 2026-07-14 · Updated 2026-07-14

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-770.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00441 38th percentileScored 2026-11-07

Fix Fixed quiche (Cloudflare): 0.29.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Cloudflare	quiche	0.15.0 to before 0.29.3	0.29.3	Patch available	CNA

quiche VendorCloudflare Affected 0.15.0 to before 0.29.3 Fixed in 0.29.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:cloudflare:quiche::::::::	—	—	Cloudflare

cpe:2.3:a:cloudflare:quiche:*:*:*:*:*:*:*:* Versions — — ·Cloudflare

Remediation

Fix · CNA quiche (Cloudflare) Fixed in 0.29.3

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-07-14
Cloudflare quiche 0.29.3
2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2026-10747 Resource exhaustion in quiche HTTP/3 and QPACK layersPriority MEDIUM 40
Show all 2 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-12707

References

Other 1

https://github.com/cloudflare/quiche/security/advisories/GHSA-4q5x-gp38-rfp4

TI-2026-12208 Cloudflare Universal SSL automatically managed CAA RRset supersedes customer-configured CAA records CVSS 4.0HIGH 7.6
TI-2025-36979 Cloudflare vite plugin exposes secrets over the built-in dev server CVSS 4.0LOW 2.9
TI-2014-08329 Out-of-bounds write in github.com/cloudflare/golz4 CVSS 3.1CRITICAL 9.8
TI-2021-02817 Arbitrary filepath traversal via URI injection CVSS 3.1CRITICAL 9.8
TI-2023-02843 Out of Bounds Slice index in cfnts leads to remote panic CVSS 3.1HIGH 8.6
TI-2026-02435 HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing CVSS 4.0CRITICAL 9.3

See all 69 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences