CVE-2024-45396: Quicly is an IETF QUIC protocol implementation

Q: How do I fix CVE-2024-45396?

quicly: upgrade to 2024-10-10. Exact commands for each OS are on this page.

Q: Is CVE-2024-45396 being exploited?

CVE-2024-45396 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2024-45396 affect?

CVE-2024-45396 affects quicly. Severity is high (CVSS 7.5). Quicly is an IETF QUIC protocol implementation. Quicly up to commtit d720707 is susceptible to a denial-of-service attack. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using quicly. The vulne

Q: How urgent is CVE-2024-45396?

Priority 43/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2024-45396 is a high-severity flaw (CVSS 7.5) affecting quicly. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Quicly is an IETF QUIC protocol implementation. Quicly up to commtit d720707 is susceptible to a denial-of-service attack. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using quicly. The vulnerability is addressed with commit 2a95896104901589c495bc41460262e64ffcad5c.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-617
Published	2024-10-11
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: dena

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2024-10-11 15:15 UTCPublished CVE record published
2026-06-17 07:54 UTCUpdated Record last modified

dena quicly UPGRADE

Affected: < 2024-10-10

Fixed in: 2024-10-10

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy quicly || rpm -q quicly || quicly --version

2. UPGRADE to 2024-10-10 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade quicly

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade quicly

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2024-45396?

quicly: upgrade to 2024-10-10. Exact commands for each OS are on this page.

Is CVE-2024-45396 being exploited?

CVE-2024-45396 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2024-45396 affect?

CVE-2024-45396 affects quicly. Severity is high (CVSS 7.5). Quicly is an IETF QUIC protocol implementation. Quicly up to commtit d720707 is susceptible to a denial-of-service attack. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using quicly. The vulne

How urgent is CVE-2024-45396?

Priority 43/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-44435 HIGH 7.5 UPGRADE Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server
CVE-2026-44436 HIGH 7.5 UPGRADE Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server
CVE-2026-44433 MEDIUM 5.3 UPGRADE Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server
CVE-2026-44434 MEDIUM 5.3 UPGRADE Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server
CVE-2025-61684 HIGH 7.5 UPGRADE Quicly, an IETF QUIC protocol implementation, is susceptible to a denial-of-service attack prior to commit d9d

References

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