7.5

CVE-2026-55213

h2o: musl libc stack overflow (QPACK)

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1, when h2o processes a QPACK instruction sent from the peer over HTTP/3, lib/http3/qpack.c might allocate an on-stack buffer as large as approximately 800 KB by calling alloca, which exceeds the default pthread stack size used by musl libc and causes the h2o server to crash with a segmentation fault while touching the guard page. This issue is fixed in commit edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
Herstellerh2o
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Produkt h2o
Version < edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.34% 0.268
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 7.5 3.9 3.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-789 Memory Allocation with Excessive Size Value

The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.

https://github.com/h2o/h2o/security/advisories/GHSA-432c-8xmj-frmq
https://github.com/h2o/h2o/commit/edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1