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CVE-2024-45397

22
FAUCET Score

CVE-2024-45397 is a vulnerability in the dena h2o HTTP server that allows attackers to bypass IP-address-based access control. When using TLS/1.3 early data with TCP Fast Open or QUIC 0-RTT, the server fails to properly validate the source IP address of incoming requests, enabling spoofed requests from otherwise blocked addresses. This vulnerability carries a CVSS score of 7.5 (HIGH), indicating a network-based attack with low complexity and potential for high confidentiality impact. There is currently no evidence of active exploitation, public exploit code, or significant community discussion regarding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 2024-10-10CPE matchmatch criteria
cpe:2.3:a:dena:h2o:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.9MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.44%
Probability of exploitation in next 30 days
EPSS Percentile
36.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0044 is in the 15th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / h2o/h2o/commit/15ed15a2efb83a77bb4baaa5a119e639c2f6898a
Patch
github.com / h2o/h2o/security/advisories/GHSA-jf2c-xjcp-wg4c
Vendor Advisory
h2o.examp1e.net / configure/http3_directives.html
Product