BSD Ports

h2o -- HTTP/2 state amplification denial of service

· VuXML entry

h2o project reports: An HTTP/2 attack can combine HPACK decompression state amplification with stalled streams. Depending on server configuration, decoded header state can be retained by stalled streams, causing excessive memory use and denial of service.

Affected versions

By system

1 still vulnerable, 1 fixed. Where VuXML applies (FreeBSD, DragonFly, FreeBSD's derivatives) a port is vulnerable while its version is in a range; pkgsrc says itself whether it lists a CVE of this advisory; OpenBSD and MidnightBSD keep no list this site reads, so their row is only an estimate: FreeBSD's ranges applied to upstream's version.

SystemPortVersionStateFixed
DragonFlywww/h2o2.3.0.d.20241011 vulnerable since 2026-06-11
NetBSDwww/h2o2.2.6nb4 not listed
FreeBSDwww/h2o20261006 fixed (109 days after)