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Package details: pkg:deb/debian/h2o@2.2.5%2Bdfsg2-6?distro=bullseye
purl pkg:deb/debian/h2o@2.2.5%2Bdfsg2-6?distro=bullseye
Vulnerabilities affecting this package (0)
Vulnerability Summary Fixed by
This package is not known to be affected by vulnerabilities.
Vulnerabilities fixed by this package (17)
Vulnerability Summary Aliases
VCID-6du6-57uz-yqaq H2O version 2.2.2 and earlier allows remote attackers to cause a denial of service in the server via specially crafted HTTP/1 header. CVE-2017-10868
VCID-a87p-5cc2-c7g4 Directory traversal vulnerability in H2O before 1.4.5 and 1.5.x before 1.5.0-beta2, when the file.dir directive is enabled, allows remote attackers to read arbitrary files via a crafted URL. CVE-2015-5638
VCID-aqt5-2ffy-9bgs HTTP/2: flood using SETTINGS frames results in unbounded memory growth CVE-2019-9515
VCID-bja7-a3uf-zqer h2o is an open source http server. In code prior to the `8c0eca3` commit h2o may attempt to access uninitialized memory. When receiving QUIC frames in certain order, HTTP/3 server-side implementation of h2o can be misguided to treat uninitialized memory as HTTP/3 frames that have been received. When h2o is used as a reverse proxy, an attacker can abuse this vulnerability to send internal state of h2o to backend servers controlled by the attacker or third party. Also, if there is an HTTP endpoint that reflects the traffic sent from the client, an attacker can use that reflector to obtain internal state of h2o. This internal state includes traffic of other connections in unencrypted form and TLS session tickets. This vulnerability exists in h2o server with HTTP/3 support, between commit 93af138 and d1f0f65. None of the released versions of h2o are affected by this vulnerability. There are no known workarounds. Users of unreleased versions of h2o using HTTP/3 are advised to upgrade immediately. CVE-2021-43848
VCID-chev-s1fh-8bhy Buffer overflow in H2O version 2.2.2 and earlier allows remote attackers to cause a denial-of-service in the server via unspecified vectors. CVE-2017-10869
VCID-e3m7-psun-vfby 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. CVE-2023-50247
VCID-gwvf-vrtr-v3dk Use-after-free vulnerability in H2O allows remote attackers to cause a denial-of-service (DoS) or obtain server certificate private keys and possibly other information. CVE-2016-7835
VCID-hbte-dsw2-y7ad golang.org/x/net/http vulnerable to ping floods Some HTTP/2 implementations are vulnerable to ping floods, potentially leading to a denial of service. The attacker sends continual pings to an HTTP/2 peer, causing the peer to build an internal queue of responses. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both. ### Specific Go Packages Affected golang.org/x/net/http2 CVE-2019-9512
GHSA-hgr8-6h9x-f7q9
VCID-k8g5-d8xx-3ye4 H2O versions 2.0.3 and earlier and 2.1.0-beta2 and earlier allows remote attackers to cause a denial-of-service (DoS) via format string specifiers in a template file via fastcgi, mruby, proxy, redirect or reproxy. CVE-2016-4864
VCID-kn2d-fupu-wbam CRLF injection vulnerability in the on_req function in lib/handler/redirect.c in H2O before 1.6.2 and 1.7.x before 1.7.0-beta3 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via a crafted URI. CVE-2016-1133
VCID-n66u-b73u-zucb golang.org/x/net/http vulnerable to a reset flood Some HTTP/2 implementations are vulnerable to a reset flood, potentially leading to a denial of service. Servers that accept direct connections from untrusted clients could be remotely made to allocate an unlimited amount of memory, until the program crashes. The attacker opens a number of streams and sends an invalid request over each stream that should solicit a stream of RST_STREAM frames from the peer. Depending on how the peer queues the RST_STREAM frames, this can consume excess memory, CPU, or both. ### Specific Go Packages Affected golang.org/x/net/http2 CVE-2019-9514
GHSA-39qc-96h7-956f
VCID-p463-b1yc-jkev H2O is an HTTP server. In versions 2.3.0-beta2 and prior, when the reverse proxy handler tries to processes a certain type of invalid HTTP request, it tries to build an upstream URL by reading from uninitialized pointer. This behavior can lead to crashes or leak of information to back end HTTP servers. Pull request number 3229 fixes the issue. The pull request has been merged to the `master` branch in commit f010336. Users should upgrade to commit f010336 or later. CVE-2023-30847
VCID-v78s-xcjx-jugh H2O version 2.2.3 and earlier allows remote attackers to cause a denial of service in the server via specially crafted HTTP/2 header. CVE-2017-10908
VCID-vgst-7jj7-cuet h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When h2o is configured as a reverse proxy and HTTP/3 requests are cancelled by the client, h2o might crash due to an assertion failure. The crash can be exploited by an attacker to mount a Denial-of-Service attack. By default, the h2o standalone server automatically restarts, minimizing the impact. However, HTTP requests that were served concurrently will still be disrupted. The vulnerability has been addressed in commit 1ed32b2. Users may disable the use of HTTP/3 to mitigate the issue. CVE-2024-45403
VCID-vmb3-588x-byfh Buffer overflow in H2O version 2.2.4 and earlier allows remote attackers to execute arbitrary code or cause a denial of service (DoS) via unspecified vectors. CVE-2018-0608
VCID-ydjm-jrpz-bbgs lib/http2/connection.c in H2O before 1.7.3 and 2.x before 2.0.0-beta5 mishandles HTTP/2 disconnection, which allows remote attackers to cause a denial of service (use-after-free and application crash) or possibly execute arbitrary code via a crafted packet. CVE-2016-4817
VCID-zbgq-j9v9-sbh5 H2O version 2.2.3 and earlier allows remote attackers to cause a denial of service in the server via unspecified vectors. CVE-2017-10872

Date Actor Action Vulnerability Source VulnerableCode Version
2026-04-16T13:24:07.500353+00:00 Debian Importer Fixing VCID-bja7-a3uf-zqer https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T13:17:06.943180+00:00 Debian Importer Fixing VCID-ydjm-jrpz-bbgs https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T13:05:15.257683+00:00 Debian Importer Fixing VCID-n66u-b73u-zucb https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T12:43:24.256768+00:00 Debian Importer Fixing VCID-kn2d-fupu-wbam https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T12:26:10.609719+00:00 Debian Importer Fixing VCID-gwvf-vrtr-v3dk https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T12:15:08.152351+00:00 Debian Importer Fixing VCID-p463-b1yc-jkev https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T12:10:10.638302+00:00 Debian Importer Fixing VCID-a87p-5cc2-c7g4 https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T11:45:59.840912+00:00 Debian Importer Fixing VCID-aqt5-2ffy-9bgs https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T11:19:09.432421+00:00 Debian Importer Fixing VCID-v78s-xcjx-jugh https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T10:58:39.244773+00:00 Debian Importer Fixing VCID-e3m7-psun-vfby https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T10:54:21.303488+00:00 Debian Importer Fixing VCID-chev-s1fh-8bhy https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T10:29:13.602188+00:00 Debian Importer Fixing VCID-6du6-57uz-yqaq https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T10:27:21.903345+00:00 Debian Importer Fixing VCID-k8g5-d8xx-3ye4 https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T10:27:06.390327+00:00 Debian Importer Fixing VCID-hbte-dsw2-y7ad https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T09:24:23.145064+00:00 Debian Importer Fixing VCID-zbgq-j9v9-sbh5 https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T09:00:37.404500+00:00 Debian Importer Fixing VCID-vmb3-588x-byfh https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T08:37:47.841095+00:00 Debian Importer Fixing VCID-vgst-7jj7-cuet https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-13T09:14:36.006093+00:00 Debian Importer Fixing VCID-bja7-a3uf-zqer https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T09:08:58.730542+00:00 Debian Importer Fixing VCID-ydjm-jrpz-bbgs https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T08:59:54.627985+00:00 Debian Importer Fixing VCID-n66u-b73u-zucb https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T08:43:25.715210+00:00 Debian Importer Fixing VCID-kn2d-fupu-wbam https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T08:30:43.469577+00:00 Debian Importer Fixing VCID-gwvf-vrtr-v3dk https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T08:22:49.594639+00:00 Debian Importer Fixing VCID-p463-b1yc-jkev https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T08:19:21.607534+00:00 Debian Importer Fixing VCID-a87p-5cc2-c7g4 https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T08:01:25.088786+00:00 Debian Importer Fixing VCID-aqt5-2ffy-9bgs https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T07:42:09.602187+00:00 Debian Importer Fixing VCID-v78s-xcjx-jugh https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T07:26:51.601478+00:00 Debian Importer Fixing VCID-e3m7-psun-vfby https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T07:23:29.791383+00:00 Debian Importer Fixing VCID-chev-s1fh-8bhy https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T07:04:40.447319+00:00 Debian Importer Fixing VCID-6du6-57uz-yqaq https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T07:03:16.483169+00:00 Debian Importer Fixing VCID-k8g5-d8xx-3ye4 https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-13T07:03:03.855576+00:00 Debian Importer Fixing VCID-hbte-dsw2-y7ad https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-11T18:16:42.084338+00:00 Debian Importer Fixing VCID-zbgq-j9v9-sbh5 https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-11T18:02:27.870730+00:00 Debian Importer Fixing VCID-vmb3-588x-byfh https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-11T17:48:14.060813+00:00 Debian Importer Fixing VCID-vgst-7jj7-cuet https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-03T07:26:24.359744+00:00 Debian Importer Fixing VCID-vgst-7jj7-cuet https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.310061+00:00 Debian Importer Fixing VCID-e3m7-psun-vfby https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.258146+00:00 Debian Importer Fixing VCID-p463-b1yc-jkev https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.230605+00:00 Debian Importer Fixing VCID-bja7-a3uf-zqer https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.203269+00:00 Debian Importer Fixing VCID-aqt5-2ffy-9bgs https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.171153+00:00 Debian Importer Fixing VCID-n66u-b73u-zucb https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.139441+00:00 Debian Importer Fixing VCID-hbte-dsw2-y7ad https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.105808+00:00 Debian Importer Fixing VCID-vmb3-588x-byfh https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.077109+00:00 Debian Importer Fixing VCID-v78s-xcjx-jugh https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.049746+00:00 Debian Importer Fixing VCID-zbgq-j9v9-sbh5 https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:24.021578+00:00 Debian Importer Fixing VCID-chev-s1fh-8bhy https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:23.994257+00:00 Debian Importer Fixing VCID-6du6-57uz-yqaq https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:23.965931+00:00 Debian Importer Fixing VCID-gwvf-vrtr-v3dk https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:23.938604+00:00 Debian Importer Fixing VCID-k8g5-d8xx-3ye4 https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:23.911429+00:00 Debian Importer Fixing VCID-ydjm-jrpz-bbgs https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:23.884015+00:00 Debian Importer Fixing VCID-kn2d-fupu-wbam https://security-tracker.debian.org/tracker/data/json 38.1.0
2026-04-03T07:26:23.856583+00:00 Debian Importer Fixing VCID-a87p-5cc2-c7g4 https://security-tracker.debian.org/tracker/data/json 38.1.0