How severe is CVE-2024-45397?

CVE-2024-45397 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2024-45397 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-45397?

CVE-2024-45397 affects Dena H2o. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2024-45397?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2024-45397 have an EU (EUVD) identifier?

Yes. CVE-2024-45397 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-41458.

When was CVE-2024-45397 published?

CVE-2024-45397 was published on 2024-10-11 and last updated on 2026-06-17.

CVE-2024-45397

CVE-2024-45397 is a medium-severity vulnerability in Dena H2o with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-290.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-41458
Weakness: CWE-290
Affected product: Dena H2o
Published: 2024-10-11
Last modified: 2026-06-17

Description

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When an HTTP request using TLS/1.3 early data on top of TCP Fast Open or QUIC 0-RTT packets is received and the IP-address-based access control is used, the access control does not detect and prohibit HTTP requests conveyed by packets with a spoofed source address. This behavior allows attackers on the network to execute HTTP requests from addresses that are otherwise rejected by the address-based access control. The vulnerability has been addressed in commit 15ed15a. Users may disable the use of TCP FastOpen and QUIC to mitigate the issue.

Frequently asked questions

What is CVE-2024-45397?: h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When an HTTP request using TLS/1.3 early data on top of TCP Fast Open or QUIC 0-RTT packets is received and the IP-address-based access control is used, the access control does not detect and prohibit HTTP requests conveyed by packets with a spoofed source address. This behavior allows attackers on the network to execute HTTP requests from addresses that are otherwise rejected by the address-based access control. The vulnerability has been addressed in commit 15ed15a. Users may disable the use of TCP FastOpen and QUIC to mitigate the issue.
How severe is CVE-2024-45397?: CVE-2024-45397 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2024-45397 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-45397?: CVE-2024-45397 affects Dena H2o. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-45397?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-45397 have an EU (EUVD) identifier?: Yes. CVE-2024-45397 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-41458.
When was CVE-2024-45397 published?: CVE-2024-45397 was published on 2024-10-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:dena:h2o:*:*:*:*:*:*:*:*

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