Quicly
CVE-2025-61684
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
|
| Impact | CVSS 7.5 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitable via remote/network. |
| Exploit ScenarioDerived | A remote attacker could exploit this vulnerability to compromise the affected system. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Quicly, an IETF QUIC protocol implementation, is susceptible to a denial-of-service attack prior to commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using Quicly. [CVSS 7.5 HIGH]
RemediationAI
A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.
Affects your stack
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Technical ContextAI · show details
Classified as CWE-20 (Improper Input Validation). Affects Quicly. Quicly, an IETF QUIC protocol implementation, is susceptible to a denial-of-service attack prior to commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using Quicly. Commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e fixes the issue.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
Lifecycle Timeline
2DescriptionGitHub Advisory
Quicly, an IETF QUIC protocol implementation, is susceptible to a denial-of-service attack prior to commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using Quicly. Commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e fixes the issue.
Executive ViewAI
CVE-2025-61684 presents notable security risk, a input validation vulnerability rated CVSS 7.5. Exploitation could compromise the security of affected deployments. A patch is available and should be applied as part of regular vulnerability management.
Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)GitHub Advisory
Denial of service in Quicly, the QUIC protocol library embedded in the H2O HTTP server, allows remote attackers to corru
Remote denial of service in quicly, the IETF QUIC implementation used by the H2O HTTP server, allows unauthenticated att
Memory exhaustion in Quicly's QUIC flow control handling allows an unauthenticated remote peer to force disproportionate
Quicly is an IETF QUIC protocol implementation. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitab
Stateless reset injection in Quicly, the IETF QUIC implementation embedded in the H2O HTTP server, allows an on-path net
Exploit-DB