The mod_headers module in the Apache HTTP Server 2.2.22 allows remote attackers to bypass "RequestHeader unset" directives by placing a head
Noroxi assessment
Priority: Monitor (action score 36/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 52.6% (FIRST EPSS); higher than 98.9% of all records.
- No special conditions are required; it is repeatable.
- Fixed version: apache2 (Debian:12) 2.4.10-2; apache2 (Debian:6.0) 2.2.16-6+squeeze14; httpd (Red Hat:enterprise_linux:6::client) 0:2.2.15-45.el6.
Low priority for now. Upgrade to apache2 (Debian:12) 2.4.10-2; apache2 (Debian:6.0) 2.2.16-6+squeeze14; httpd (Red Hat:enterprise_linux:6::client) 0:2.2.15-45.el6 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
The mod_headers module in the Apache HTTP Server 2.2.22 allows remote attackers to bypass "RequestHeader unset" directives by placing a header in the trailer portion of data sent with chunked transfer coding. NOTE: the vendor states "this is not a security issue in httpd as such."
- Published
- Apr 15, 2014
- Updated
- Jun 16, 2026
- EPSS
- 52.6% · 98th percentile
- CWE
- —
Report tools
Action score
36
Monitor
Low priority for now.
- CVSS
- 20 / 40 · 5.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 16 / 30 · 52.6%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| apache | http server | cpe:2.3:a:apache:http_server |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux eus | cpe:2.3:o:redhat:enterprise_linux_eus |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux server aus | cpe:2.3:o:redhat:enterprise_linux_server_aus |
| redhat | enterprise linux server tus | cpe:2.3:o:redhat:enterprise_linux_server_tus |
| redhat | enterprise linux workstation | cpe:2.3:o:redhat:enterprise_linux_workstation |
| redhat | jboss enterprise web server | cpe:2.3:a:redhat:jboss_enterprise_web_server |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
| oracle | enterprise manager ops center | cpe:2.3:a:oracle:enterprise_manager_ops_center |
| oracle | http server | cpe:2.3:a:oracle:http_server |
| oracle | linux | cpe:2.3:o:oracle:linux |
and 4 more
Using http server? Add it to your stack and be the first to know about CVEs like this one. (Apache HTTP)
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache http server2.2.0
- apache http server2.2.10
- apache http server2.2.11
- apache http server2.2.12
- apache http server2.2.13
- apache http server2.2.14
- apache http server2.2.15
- apache http server2.2.16
- apache http server2.2.17
- apache http server2.2.18
- apache http server2.2.19
- apache http server2.2.2
- apache http server2.2.20
- apache http server2.2.21
- apache http server2.2.22
- apache http server2.2.23
- apache http server2.2.24
- apache http server2.2.25
- apache http server2.2.26
- apache http server2.2.27
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | apache2 | before 2.4.10-2 | 2.4.10-2 |
| Debian:6.0 | apache2 | before 2.2.16-6+squeeze14 | 2.2.16-6+squeeze14 |
| Red Hat:enterprise_linux:6::client | httpd | before 0:2.2.15-45.el6 | 0:2.2.15-45.el6 |
| Red Hat:enterprise_linux:6::client | httpd-debuginfo | before 0:2.2.15-45.el6 | 0:2.2.15-45.el6 |
| Red Hat:enterprise_linux:6::client | httpd-devel | before 0:2.2.15-45.el6 | 0:2.2.15-45.el6 |
| Red Hat:enterprise_linux:6::client | httpd-manual | before 0:2.2.15-45.el6 | 0:2.2.15-45.el6 |
| Red Hat:enterprise_linux:6::client | httpd-tools | before 0:2.2.15-45.el6 | 0:2.2.15-45.el6 |
| Red Hat:enterprise_linux:6::client | mod_ssl | before 1:2.2.15-45.el6 | 1:2.2.15-45.el6 |
| Red Hat:enterprise_linux:7::client | httpd | before 0:2.4.6-31.el7 | 0:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | httpd-debuginfo | before 0:2.4.6-31.el7 | 0:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | httpd-devel | before 0:2.4.6-31.el7 | 0:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | httpd-manual | before 0:2.4.6-31.el7 | 0:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | httpd-tools | before 0:2.4.6-31.el7 | 0:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | mod_ldap | before 0:2.4.6-31.el7 | 0:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | mod_proxy_html | before 1:2.4.6-31.el7 | 1:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | mod_session | before 0:2.4.6-31.el7 | 0:2.4.6-31.el7 |
| Red Hat:enterprise_linux:7::client | mod_ssl | before 1:2.4.6-31.el7 | 1:2.4.6-31.el7 |
| Red Hat:jboss_enterprise_web_server:2::el5 | httpd | before 0:2.2.26-41.ep6.el5 | 0:2.2.26-41.ep6.el5 |
| Red Hat:jboss_enterprise_web_server:2::el5 | httpd-devel | before 0:2.2.26-41.ep6.el5 | 0:2.2.26-41.ep6.el5 |
| Red Hat:jboss_enterprise_web_server:2::el5 | httpd-manual | before 0:2.2.26-41.ep6.el5 | 0:2.2.26-41.ep6.el5 |
| Red Hat:jboss_enterprise_web_server:2::el5 | httpd-tools | before 0:2.2.26-41.ep6.el5 | 0:2.2.26-41.ep6.el5 |
| Red Hat:jboss_enterprise_web_server:2::el5 | mod_cluster-native | before 0:1.2.9-6.Final_redhat_2.ep6.el5 | 0:1.2.9-6.Final_redhat_2.ep6.el5 |
| Red Hat:jboss_enterprise_web_server:2::el5 | mod_ssl | before 1:2.2.26-41.ep6.el5 | 1:2.2.26-41.ep6.el5 |
| Red Hat:jboss_enterprise_web_server:2::el6 | httpd | before 0:2.2.26-41.ep6.el6 | 0:2.2.26-41.ep6.el6 |
+96
Same product
apache: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-42013Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)KEV99Now
- CVE-2021-41773Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49KEV99Now
- CVE-2024-38475Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path.KEV96Now
- CVE-2019-0211In Apache HTTP Server 2.4 releases 2.4.17 to 2.4.38, with MPM event, worker or prefork, code executing in less-privileged child processes orKEV81Now
- CVE-2021-44790Possible buffer overflow when parsing multipart content in mod_lua of Apache HTTP Server 2.4.51 and earlier68This week
- CVE-2010-0425modules/arch/win32/mod_isapi.c in mod_isapi in the Apache HTTP Server 2.0.37 through 2.0.63, 2.2.0 through 2.2.14, and 2.3.x before 2.3.7, w68This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:apache2 | 2.4.10-2 · Debian:12 | Package registry (OSV) |
| red hat:httpd | 0:2.4.6-31.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:httpd-debuginfo | 0:2.4.6-31.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:httpd-devel | 0:2.4.6-31.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:httpd24-httpd | 0:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-debuginfo | 0:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-devel | 0:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-manual | 0:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-tools | 0:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-mod_ldap | 0:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-mod_proxy_html | 1:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-mod_session | 0:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| red hat:httpd24-mod_ssl | 1:2.4.6-22.el6 · Red Hat:rhel_software_collections:1::el6 | Package registry (OSV) |
| suse:apache2 | 2.4.10-12.1 · SUSE:Linux Enterprise Software Development Kit 12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- P · data or configuration can be modified
- Availability
- none
- Attack complexity
- Low
- Confidentiality impact
- None
- Integrity impact
- P
- Availability impact
- None
Weakness class (CWE)
—
CVSS vector
AV:N/AC:L/Au:N/C:N/I:P/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- lists.apple.com/archives/security-announce/2015/Sep/msg00004.html
- marc.info/?l=apache-httpd-dev&m=139636309822854&w=2
- marc.info/?l=bugtraq&m=143403519711434&w=2
- marc.info/?l=bugtraq&m=144493176821532&w=2
- rhn.redhat.com/errata/RHSA-2015-0325.html
- rhn.redhat.com/errata/RHSA-2015-1249.html
- rhn.redhat.com/errata/RHSA-2015-2661.html
- rhn.redhat.com/errata/RHSA-2016-0061.html
- rhn.redhat.com/errata/RHSA-2016-0062.html
- svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x/CHANGES
- svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_http.c
- svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_http.c?r1=1610674&r2=1610814&diff_format=h
- www.mandriva.com/security/advisories?name=MDVSA-2014:174
- www.oracle.com/technetwork/topics/security/bulletinjan2015-2370101.html
- www.oracle.com/technetwork/topics/security/cpujan2015-1972971.html
- www.oracle.com/technetwork/topics/security/cpujan2016-2367955.html
- www.oracle.com/technetwork/topics/security/cpujul2015-2367936.html
- www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
- www.securityfocus.com/bid/66550
Vendor advisories and official records. Exploit/PoC links are deliberately left out.