CVE-2024-25622
H2O ignores headers configuration directives
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The configuration directives provided by the headers handler allows users to modify the response headers being sent by h2o. The configuration file of h2o has scopes, and the inner scopes (e.g., path level) are expected to inherit the configuration defined in outer scopes (e.g., global level). However, if a header directive is used in the inner scope, all the definition in outer scopes are ignored. This can lead to headers not being modified as expected. Depending on the headers being added or removed unexpectedly, this behavior could lead to unexpected client behavior. This vulnerability is fixed in commit 123f5e2b65dcdba8f7ef659a00d24bd1249141be.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
3.1
H2O ignores headers configuration directives
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The configuration directives provided by the headers handler allows users to modify the response headers being sent by h2o. The configuration file of h2o has scopes, and the inner scopes (e.g., path level) are expected to inherit the configuration defined in outer scopes (e.g., global level). However, if a header directive is used in the inner scope, all the definition in outer scopes are ignored. This can lead to headers not being modified as expected. Depending on the headers being added or removed unexpectedly, this behavior could lead to unexpected client behavior. This vulnerability is fixed in commit 123f5e2b65dcdba8f7ef659a00d24bd1249141be.
- Record
CVE-2024-25622- CVSS 3.1
- 3.1 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N - Weakness
- CWE-670
- Updated
- 2026-11-02
EUVDEUVD-2024-22943
3.1
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The configuration directives provided by the headers handler allows users to modify the response headers being sent by h2o. The configuration file of h2o has scopes, and the inner scopes (e.g., path level) are expected to inherit the configuration defined in outer scopes (e.g., global level). However, if a header directive is used in the inner scope, all the definition in outer scopes are ignored. This can lead to headers not being modified as expected. Depending on the headers being added or removed unexpectedly, this behavior could lead to unexpected client behavior. This vulnerability is fixed in commit 123f5e2b65dcdba8f7ef659a00d24bd1249141be.
- Record
EUVD-2024-22943- CVSS 3.1
- 3.1 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N - Updated
- 2026-11-03
NVD
3.1
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The configuration directives provided by the headers handler allows users to modify the response headers being sent by h2o. The configuration file of h2o has scopes, and the inner scopes (e.g., path level) are expected to inherit the configuration defined in outer scopes (e.g., global level). However, if a header directive is used in the inner scope, all the definition in outer scopes are ignored. This can lead to headers not being modified as expected. Depending on the headers being added or removed unexpectedly, this behavior could lead to unexpected client behavior. This vulnerability is fixed in commit 123f5e2b65dcdba8f7ef659a00d24bd1249141be.
- Record
CVE-2024-25622- CVSS 3.1
- 3.1 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N - CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-670
- Updated
- 2026-11-02
OSV
3.1
H2O ignores headers configuration directives
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The configuration directives provided by the headers handler allows users to modify the response headers being sent by h2o. The configuration file of h2o has scopes, and the inner scopes (e.g., path level) are expected to inherit the configuration defined in outer scopes (e.g., global level). However, if a header directive is used in the inner scope, all the definition in outer scopes are ignored. This can lead to headers not being modified as expected. Depending on the headers being added or removed unexpectedly, this behavior could lead to unexpected client behavior. This vulnerability is fixed in commit 123f5e2b65dcdba8f7ef659a00d24bd1249141be.
- Record
CVE-2024-25622- CVSS 3.1
- 3.1 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N - Weakness
- CWE-670
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2024-25622
4.3
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The configuration directives provided by the headers handler allows users to modify the response headers being sent by h2o. The configuration file of h2o has scopes, and the inner scopes (e.g., path level) are expected to inherit the configuration defined in outer scopes (e.g., global level). However, if a header directive is used in the inner scope, all the definition in outer scopes are ignored. This can lead to headers not being modified as expected. Depending on the headers being added or removed unexpectedly, this behavior could lead to unexpected client behavior. This vulnerability is fixed in commit 123f5e2b65dcdba8f7ef659a00d24bd1249141be.
- Record
DEBIAN-CVE-2024-25622- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2024-25622
3.1
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The configuration directives provided by the headers handler allows users to modify the response headers being sent by h2o. The configuration file of h2o has scopes, and the inner scopes (e.g., path level) are expected to inherit the configuration defined in outer scopes (e.g., global level). However, if a header directive is used in the inner scope, all the definition in outer scopes are ignored. This can lead to headers not being modified as expected. Depending on the headers being added or removed unexpectedly, this behavior could lead to unexpected client behavior. This vulnerability is fixed in commit 123f5e2b65dcdba8f7ef659a00d24bd1249141be.
- Record
UBUNTU-CVE-2024-25622- CVSS 3.1
- 3.1 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N - CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
h2oDebian:12 |
All versions, plus listed versions 2.2.5+dfsg2-102.2.5+dfsg2-112.2.5+dfsg2-72.2.5+dfsg2-82.2.5+dfsg2-8.12.2.5+dfsg2-8.1~exp12.2.5+dfsg2-9 |
None known |
h2oUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 2.2.3+dfsg-22.2.4+dfsg-12.2.4+dfsg-1build12.2.4+dfsg-1ubuntu0.1~esm2 |
None known |
h2oUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 2.2.5+dfsg2-32.2.5+dfsg2-3build12.2.5+dfsg2-3ubuntu0.1~esm1 |
None known |
h2oUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 2.2.5+dfsg2-62.2.5+dfsg2-6.12.2.5+dfsg2-6.1ubuntu12.2.5+dfsg2-6.1ubuntu22.2.5+dfsg2-6.1ubuntu2+esm1 |
None known |
h2oUbuntu:24.04:LTS |
All versions, plus listed versions 2.2.5+dfsg2-72.2.5+dfsg2-82.2.5+dfsg2-8.1ubuntu12.2.5+dfsg2-8.1ubuntu22.2.5+dfsg2-8.1ubuntu3 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-25622 is a low vulnerability (CVSS 3.1) in Dena H2o, published October 11, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.46%, the 40th percentile. No source names a fixed version.
References
github.com/h2o/h2o/security/advisories/GHSA-5m7v-cj65-h6pj
github.com/h2o/h2o/issues/3332
github.com/h2o/h2o/commit/123f5e2b65dcdba8f7ef659a00d24bd1249141be
github.com/CVEProject/cvelistV5/tree/main/cves/2024/25xxx/CVE-2024-25622.json
nvd.nist.gov/vuln/detail/CVE-2024-25622
security-tracker.debian.org/tracker/CVE-2024-25622
ubuntu.com/security/CVE-2024-25622
cve.org/CVERecord?id=CVE-2024-25622