TI-2026-10747 Aliases CVE-2026-12523

Resource exhaustion in quiche HTTP/3 and QPACK layers

MEDIUM 40CWE-400Published 2026-07-14 · Updated 2026-07-15

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-400.

Summary

Summary Cloudflare quiche's HTTP/3 layer was discovered to be vulnerable to resource exhaustion (i.e., memory) by means of specially crafted HTTP/3 frames. Impact HTTP/3 defines multiple frame types to support HTTP message exchanges and connection management. Each frame has a length and a payload whose length depends on the frame type. quiche was found to be vulnerable when parsing some frame types to pre-allocating memory based on the declared length. An attacker would not need to send the number of declared bytes to trigger this issue. In addition, quiche was found to not apply QPACK decompression limits correctly. This could allow an attacker to send specially crafted HEADERS frames that would cause more memory commitment than otherwise advertised by MAX_FIELD_SECTION_SIZE (configured by set_max_field_section_size()). Mitigation: * Users are requested to upgrade to quiche 0.29.3 which is the earliest version containing the fix for this issue. Credits: Disclosed responsibly by Sébastien Féry

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00532 45th 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	0.1.0 to before 0.29.3	0.29.3	Patch available	CNA

quiche VendorCloudflare Affected 0.1.0 to before 0.29.3 Fixed in 0.29.3 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:cloudflare:quiche::::::rust::*	0.1.0 to before 0.29.3	Vulnerable	Cloudflare

cpe:2.3:a:cloudflare:quiche:*:*:*:*:*:rust:*:* Versions 0.1.0 to before 0.29.3 Vulnerable ·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-2026-10866 Unbounded path event queue growth in quiche via peer-driven source connection ID rotationPriority LOW 39
Show all 2 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-12523

References

Advisory 1

https://github.com/cloudflare/quiche/security/advisories/GHSA-4fgf-9xrr-88gf

TI-2025-06417 Infinite loop triggered by connection ID retirement CVSS 4.0HIGH 8.7
TI-2025-04316 Incorrect congestion window growth by invalid ACK ranges CVSS 3.1HIGH 7.5
TI-2024-01642 Unlimited resource allocation by QUIC CRYPTO frames flooding in quiche CVSS 3.1HIGH 7.5
TI-2025-04315 Incorrect congestion window growth by optimistic ACK CVSS 3.1MEDIUM 5.3
TI-2024-01317 Unbounded storage of information related to connection ID retirement, in quiche CVSS 3.1MEDIUM 5.3
TI-2023-05687 Unbounded queuing of path validation messages in cloudflare-quiche CVSS 3.1MEDIUM 5.3

Sources

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