httpd: Incomplete handling of LimitRequestFields directive in mod_http2
Published Dec 5, 2016
7.5
HIGHCVSS 3.0
EPSS 79.07%
Description
The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.
Affected products
-
- Version 2.4.17 - 2.4.23StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | n/a |
|
- 2.4.17
- 2.4.18
- 2.4.19
- 2.4.20
- 2.4.21
- 2.4.22
- 2.4.23
No data.
JBoss Core Services on RHEL 6
jbcs-httpd24-httpd-0:2.4.23-120.jbcs.el6
Fixed · RHSA-2017:1414
JBoss Core Services on RHEL 6
jbcs-httpd24-mod_security-0:2.9.1-19.GA.jbcs.el6
Fixed · RHSA-2017:1414
JBoss Core Services on RHEL 6
jbcs-httpd24-openssl-1:1.0.2h-13.jbcs.el6
Fixed · RHSA-2017:1414
JBoss Core Services on RHEL 7
jbcs-httpd24-httpd-0:2.4.23-120.jbcs.el7
Fixed · RHSA-2017:1413
JBoss Core Services on RHEL 7
jbcs-httpd24-mod_security-0:2.9.1-19.GA.jbcs.el7
Fixed · RHSA-2017:1413
JBoss Core Services on RHEL 7
jbcs-httpd24-openssl-1:1.0.2h-13.jbcs.el7
Fixed · RHSA-2017:1413
Red Hat JBoss Core Services
n/a
Fixed · RHSA-2017:1415
Red Hat Software Collections for Red Hat Enterprise Linux 6
httpd24-httpd-0:2.4.25-9.el6
Fixed · RHSA-2017:1161
Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS
httpd24-httpd-0:2.4.25-9.el6
Fixed · RHSA-2017:1161
Red Hat Software Collections for Red Hat Enterprise Linux 7
httpd24-httpd-0:2.4.25-9.el7
Fixed · RHSA-2017:1161
Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS
httpd24-httpd-0:2.4.25-9.el7
Fixed · RHSA-2017:1161
Red Hat Directory Server 8
httpd
Not affected
Red Hat Enterprise Linux 5
httpd
Not affected
Red Hat Enterprise Linux 6
httpd
Not affected
Red Hat Enterprise Linux 7
httpd
Not affected
Red Hat JBoss Enterprise Application Platform 5
httpd
Not affected
Red Hat JBoss Enterprise Application Platform 6
httpd
Not affected
Red Hat JBoss Enterprise Application Platform 6
httpd22
Not affected
Red Hat JBoss Enterprise Web Server 1
httpd
Not affected
Red Hat JBoss Enterprise Web Server 2
httpd
Not affected
Red Hat JBoss Enterprise Web Server 2
httpd22
Not affected
Red Hat JBoss Web Server 3
httpd
Not affected
Red Hat JBoss Web Server 3
httpd24
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| JBoss Core Services on RHEL 6 | jbcs-httpd24-httpd-0:2.4.23-120.jbcs.el6 | Fixed | RHSA-2017:1414 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-mod_security-0:2.9.1-19.GA.jbcs.el6 | Fixed | RHSA-2017:1414 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-openssl-1:1.0.2h-13.jbcs.el6 | Fixed | RHSA-2017:1414 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-httpd-0:2.4.23-120.jbcs.el7 | Fixed | RHSA-2017:1413 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-mod_security-0:2.9.1-19.GA.jbcs.el7 | Fixed | RHSA-2017:1413 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-openssl-1:1.0.2h-13.jbcs.el7 | Fixed | RHSA-2017:1413 |
| Red Hat JBoss Core Services | n/a | Fixed | RHSA-2017:1415 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | httpd24-httpd-0:2.4.25-9.el6 | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | httpd24-httpd-0:2.4.25-9.el6 | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | httpd24-httpd-0:2.4.25-9.el7 | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | httpd24-httpd-0:2.4.25-9.el7 | Fixed | RHSA-2017:1161 |
| Red Hat Directory Server 8 | httpd | Not affected | n/a |
| Red Hat Enterprise Linux 5 | httpd | Not affected | n/a |
| Red Hat Enterprise Linux 6 | httpd | Not affected | n/a |
| Red Hat Enterprise Linux 7 | httpd | Not affected | n/a |
| Red Hat JBoss Enterprise Application Platform 5 | httpd | Not affected | n/a |
| Red Hat JBoss Enterprise Application Platform 6 | httpd | Not affected | n/a |
| Red Hat JBoss Enterprise Application Platform 6 | httpd22 | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 1 | httpd | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 2 | httpd | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 2 | httpd22 | Not affected | n/a |
| Red Hat JBoss Web Server 3 | httpd | Not affected | n/a |
| Red Hat JBoss Web Server 3 | httpd24 | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
Red Hat mitigation
As a temporary workaround - HTTP/2 can be disabled by changing the configuration by removing h2 and h2c from the Protocols line(s) in the configuration file. The resulting line should read: Protocols http/1.1
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
AV:N/AC:L/Au:N/C:N/I:N/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (56 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 79.07% (0.79070) | 99.59th | v5 (v2026.06.15) |
| Sep 22, 2026 | 79.07% (0.79070) | 99.58th | v5 (v2026.06.15) |
| Sep 21, 2026 | 76.95% (0.76952) | 99.54th | v5 (v2026.06.15) |
| Sep 6, 2026 | 79.07% (0.79070) | 99.57th | v5 (v2026.06.15) |
| Sep 5, 2026 | 76.95% (0.76952) | 99.53th | v5 (v2026.06.15) |
| Aug 30, 2026 | 79.07% (0.79070) | 99.57th | v5 (v2026.06.15) |
| Aug 28, 2026 | 76.95% (0.76952) | 99.53th | v5 (v2026.06.15) |
| Aug 24, 2026 | 79.07% (0.79070) | 99.56th | v5 (v2026.06.15) |
| Aug 23, 2026 | 76.95% (0.76952) | 99.53th | v5 (v2026.06.15) |
| Jun 15, 2026 | 79.07% (0.79070) | 99.55th | v5 (v2026.06.15) |
| Jun 11, 2026 | 67.72% (0.67721) | 98.60th | v4 (v2025.03.14) |
| May 31, 2026 | 71.52% (0.71517) | 98.75th | v4 (v2025.03.14) |
| Mar 4, 2026 | 68.26% (0.68259) | 98.56th | v4 (v2025.03.14) |
| Mar 1, 2026 | 55.49% (0.55491) | 98.04th | v4 (v2025.03.14) |
| Feb 4, 2026 | 68.26% (0.68259) | 98.55th | v4 (v2025.03.14) |
| Feb 1, 2026 | 55.49% (0.55491) | 98.01th | v4 (v2025.03.14) |
| Jan 4, 2026 | 68.26% (0.68259) | 98.54th | v4 (v2025.03.14) |
| Jan 1, 2026 | 55.49% (0.55491) | 97.99th | v4 (v2025.03.14) |
| Dec 28, 2025 | 68.26% (0.68259) | 98.53th | v4 (v2025.03.14) |
| Dec 27, 2025 | 58.56% (0.58560) | 98.13th | v4 (v2025.03.14) |
| Dec 4, 2025 | 68.26% (0.68259) | 98.52th | v4 (v2025.03.14) |
| Dec 1, 2025 | 55.49% (0.55491) | 97.97th | v4 (v2025.03.14) |
| Nov 24, 2025 | 68.26% (0.68259) | 98.52th | v4 (v2025.03.14) |
| Nov 4, 2025 | 71.78% (0.71780) | 98.67th | v4 (v2025.03.14) |
| Nov 1, 2025 | 65.63% (0.65625) | 98.43th | v4 (v2025.03.14) |
| Oct 28, 2025 | 71.78% (0.71780) | 98.67th | v4 (v2025.03.14) |
| Oct 27, 2025 | 62.91% (0.62913) | 98.30th | v4 (v2025.03.14) |
| Oct 4, 2025 | 71.52% (0.71517) | 98.67th | v4 (v2025.03.14) |
| Oct 1, 2025 | 65.31% (0.65313) | 98.44th | v4 (v2025.03.14) |
| Sep 4, 2025 | 62.63% (0.62627) | 98.32th | v4 (v2025.03.14) |
| Sep 1, 2025 | 56.73% (0.56733) | 98.06th | v4 (v2025.03.14) |
| Aug 4, 2025 | 62.63% (0.62627) | 98.29th | v4 (v2025.03.14) |
| Aug 1, 2025 | 56.73% (0.56733) | 98.03th | v4 (v2025.03.14) |
| Jul 30, 2025 | 62.63% (0.62627) | 98.29th | v4 (v2025.03.14) |
| Jul 4, 2025 | 71.55% (0.71553) | 98.64th | v4 (v2025.03.14) |
| Jul 1, 2025 | 66.74% (0.66741) | 98.45th | v4 (v2025.03.14) |
| Jun 4, 2025 | 71.55% (0.71553) | 98.63th | v4 (v2025.03.14) |
| Jun 1, 2025 | 66.74% (0.66741) | 98.43th | v4 (v2025.03.14) |
| May 4, 2025 | 71.55% (0.71553) | 98.62th | v4 (v2025.03.14) |
| May 1, 2025 | 66.74% (0.66741) | 98.43th | v4 (v2025.03.14) |
| Mar 30, 2025 | 71.55% (0.71553) | 98.64th | v4 (v2025.03.14) |
| Mar 29, 2025 | 53.45% (0.53449) | 97.06th | v4 (v2025.03.14) |
| Mar 28, 2025 | 71.55% (0.71553) | 98.63th | v4 (v2025.03.14) |
| Mar 27, 2025 | 53.45% (0.53449) | 97.63th | v4 (v2025.03.14) |
| Mar 20, 2025 | 71.55% (0.71553) | 98.67th | v4 (v2025.03.14) |
| Mar 19, 2025 | 53.45% (0.53449) | 97.67th | v4 (v2025.03.14) |
| Mar 17, 2025 | 71.55% (0.71553) | 98.64th | v4 (v2025.03.14) |
| Feb 2, 2025 | 12.66% (0.12656) | 95.49th | v3 (v2023.03.01) |
| Dec 17, 2024 | 14.75% (0.14746) | 95.76th | v3 (v2023.03.01) |
| Dec 12, 2024 | 4.67% (0.04673) | 92.92th | v3 (v2023.03.01) |
| Sep 27, 2024 | 3.74% (0.03742) | 91.97th | v3 (v2023.03.01) |
| Jun 1, 2023 | 2.67% (0.02675) | 88.89th | v3 (v2023.03.01) |
| Mar 11, 2023 | 2.66% (0.02655) | 88.73th | v3 (v2023.03.01) |
| Mar 7, 2023 | 2.69% (0.02689) | 88.80th | v3 (v2023.03.01) |
| Mar 6, 2023 | 72.65% (0.72654) | 99.26th | v2 (v2022.01.01) |
| Feb 4, 2022 | 72.65% (0.72654) | 99.10th | v2 (v2022.01.01) |
References (34)
- http://packetstormsecurity.com/files/140023/Apache-HTTPD-Web-Server-2.4.23-Memory-Exhaustion.html x_refsource_MISCExploitThird Party AdvisoryVDB Entry
- http://rhn.redhat.com/errata/RHSA-2017-1415.html vendor-advisoryx_refsource_REDHAT
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- https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E mailing-listx_refsource_MLIST
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Change history (0)
No recorded changes yet.