The Apache HTTP Server 2.4.17 and 2.4.18, when mod_http2 is enabled, does not limit the…
Priority MEDIUM 43CWE-399Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.0 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-399 and the CVSS impact.
Summary
The Apache HTTP Server 2.4.17 and 2.4.18, when mod_http2 is enabled, does not limit the number of simultaneous stream workers for a single HTTP/2 connection, which allows remote attackers to cause a denial of service (stream-processing outage) via modified flow-control windows.
Why it matters now
EPSS 0.15923 96th percentileScored 2026-11-07
Fix Fixed Red Hat: 1 advisory
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
Red Hat 1 advisory
- RHSA-2017:1161 Released 2017-04-26 · Red Hat rating Moderatehttpd24-httpd security, bug fix, and enhancement update
- Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) httpd24-httpd-2.4.25-9.el6, httpd24-httpd-devel-2.4.25-9.el6, httpd24-httpd-manual-2.4.25-9.el6 +5
- Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) httpd24-httpd-2.4.25-9.el7, httpd24-httpd-devel-2.4.25-9.el7, httpd24-httpd-manual-2.4.25-9.el7 +5
- Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.7) httpd24-httpd-2.4.25-9.el6, httpd24-httpd-devel-2.4.25-9.el6, httpd24-httpd-manual-2.4.25-9.el6 +5
- Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.3) httpd24-httpd-2.4.25-9.el7, httpd24-httpd-devel-2.4.25-9.el7, httpd24-httpd-manual-2.4.25-9.el7 +5
- Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) httpd24-httpd-2.4.25-9.el6, httpd24-httpd-devel-2.4.25-9.el6, httpd24-httpd-manual-2.4.25-9.el6 +5
- Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) httpd24-httpd-2.4.25-9.el7, httpd24-httpd-devel-2.4.25-9.el7, httpd24-httpd-manual-2.4.25-9.el7 +5
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.7) | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.3) | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2017:1161 |
| Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2017:1161 |
Not affected: 10 products
- CloudForms Management Engine 5
- Red Hat Directory Server 8
- Red Hat Enterprise Linux 5
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat JBoss Enterprise Application Platform 5
- Red Hat JBoss Enterprise Application Platform 6
- Red Hat JBoss Enterprise Web Server 1
- Red Hat JBoss Enterprise Web Server 2
- Red Hat JBoss Enterprise Web Server 3
Timeline
- 2026-10-02 Threatist record created from CVE-2016-1546
- 2026-10-03 Alias added: GHSA-f6fj-787v-v59m
References
Advisory 2
Other 17
- http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html
- http://www.apache.org/dist/httpd/CHANGES_2.4
- http://svn.apache.org/viewvc?view=revision&revision=1733727
- http://www.oracle.com/technetwork/topics/security/bulletinoct2016-3090566.html
- https://security.netapp.com/advisory/ntap-20180601-0001/
- [httpd-cvs] 20190815 svn commit: r1048743 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html
- [httpd-cvs] 20190815 svn commit: r1048742 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html
- [httpd-cvs] 20200401 svn commit: r1058586 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html
- [httpd-cvs] 20200401 svn commit: r1058587 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/
- [httpd-cvs] 20210330 svn commit: r1073140 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html
- [httpd-cvs] 20210330 svn commit: r1888194 [10/13] - /httpd/site/trunk/content/security/json/
- [httpd-cvs] 20210330 svn commit: r1073139 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/json/
- [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/
- [httpd-cvs] 20210330 svn commit: r1073146 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities-httpd.xml security/vulnerabilities_22.html security/vulnerabilities_24.html
- [httpd-cvs] 20210330 svn commit: r1073149 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/
- [httpd-cvs] 20210606 svn commit: r1075470 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html
More Apache Http Server vulnerabilities
- TI-2021-18535 Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) KEVCVSS 3.1CRITICAL 9.8
- TI-2021-18417 Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49 KEVCVSS 3.1CRITICAL 9.8
- TI-2024-25716 Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path. KEVCVSS 3.1CRITICAL 9.1
- TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
- TI-2019-00184 Use after free in Apache HTTP Server KEVCVSS 3.1HIGH 7.8
- TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2016-1546 · CVE Program
- CVE-2016-1546 · NVD
- FIRST EPSS
- GHSA-f6fj-787v-v59m · GitHub Advisory Database · CC BY 4.0
- CVE-2016-1546 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences