High severity · published Dec 12, 2023
CVE-2023-50247
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3
7.5
CVSS
0.9%
EPSS
No
On KEV
Description
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The QUIC stack (quicly), as used by H2O up to commit 43f86e5 (in version 2.3.0-beta and prior), is susceptible to a state exhaustion attack. When H2O is serving HTTP/3, a remote attacker can exploit this vulnerability to progressively increase the memory retained by the QUIC stack. This can eventually cause H2O to abort due to memory exhaustion. The vulnerability has been resolved in commit d67e81d03be12a9d53dc8271af6530f40164cd35. HTTP/1 and HTTP/2 are not affected by this vulnerability as they do not use QUIC. Administrators looking to mitigate this issue without upgrading can disable HTTP/3 support.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 58% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
H2
H2o · Dena
through 2.2.6; 2.3.0; 2.3.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-50247
CVE.org
https://www.cve.org/CVERecord?id=CVE-2023-50247
Patch
https://github.com/h2o/h2o/commit/d67e81d03be12a9d53dc8271af6530f40164cd35
Patch
https://github.com/h2o/h2o/security/advisories/GHSA-2ch5-p59c-7mv6
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