# What is CVE-2013-5704?

> CVE-2013-5704 is a medium-severity flaw (CVSS 5.0) in HTTP Server from Apache, published on 15 April 2014. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 53%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2013-5704

## At a glance

- **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
- **Precursor Intelligence risk score:** 45 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** Medium (CVSS 5.0 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 53% (latest exploit-likelihood forecast)
- **Published:** 15 April 2014
- **Record last updated:** 12 April 2025
- **Main product:** HTTP Server from Apache
- **Affected products:** 16

## What is CVE-2013-5704? In plain terms

It can be attacked from anywhere on the internet without logging in. If it works, the attacker can change some data.

### The official description

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."

### What kind of flaw is it?

- Unknown: Unknown

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Easy: no special conditions
- Login needed first: No login needed
- What an attacker gets: Can change some data

Severity vector: `AV:N/AC:L/Au:N/C:N/I:P/A:N`

## Is CVE-2013-5704 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 53%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 53%, 53%, 53%, 53%, 53%, 53%, 53%.

### Timeline

- 15 April 2014: Published
- 12 April 2025: Record last updated
- 11 June 2025: Exploit likelihood fell
- 5 July 2025: Exploit likelihood jumped

### How Precursor Intelligence ranks it

CVE-2013-5704 scores **45 out of 100 (Medium)**, with the action "Plan remediation".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2013-5704?

The published record lists 16 products. Versions are as published: "before 12.1.4" means every version up to, but not including, 12.1.4.

- [HTTP Server](https://www.precursorintelligence.com/product/apache/http_server) by [Apache](https://www.precursorintelligence.com/vendors/apache) (Application): 2.2.0, 2.2.2, 2.2.3, 2.2.4, 2.2.5, 2.2.6, 2.2.8, 2.2.9, 2.2.10, 2.2.11, 2.2.12, 2.2.13, 2.2.14, 2.2.15, 2.2.16, 2.2.17, 2.2.18, 2.2.19, 2.2.20, 2.2.21, 2.2.22, 2.2.23, 2.2.24, 2.2.25, 2.2.26, 2.2.27, 2.4.1, 2.4.2, 2.4.3, 2.4.4, 2.4.6, 2.4.7, 2.4.9, 2.4.10
- [Enterprise Linux Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 7.3, 7.4, 7.5, 7.6, 7.7
- [Enterprise Manager Ops Center](https://www.precursorintelligence.com/product/oracle/enterprise_manager_ops_center) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Application): before 12.1.4, 12.1.4, 12.2.0, 12.2.1, 12.3.0
- [Enterprise Linux Server Aus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server_aus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 7.3, 7.4, 7.6, 7.7
- [HTTP Server](https://www.precursorintelligence.com/product/oracle/http_server) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Application): 10.1.3.5.0, 11.1.1.7.0, 12.1.2.0, 12.1.3.0
- [Ubuntu Linux](https://www.precursorintelligence.com/product/canonical/ubuntu_linux) by [Canonical](https://www.precursorintelligence.com/vendors/canonical) (Operating system): 10.04, 12.04, 14.04, 14.10
- [Enterprise Linux](https://www.precursorintelligence.com/product/redhat/enterprise_linux) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 5.0, 6.0, 7.0
- [Enterprise Linux Server Tus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server_tus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 7.3, 7.6, 7.7
- [Enterprise Linux Desktop](https://www.precursorintelligence.com/product/redhat/enterprise_linux_desktop) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.0, 7.0
- [Enterprise Linux Server](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.0, 7.0
- [Enterprise Linux Workstation](https://www.precursorintelligence.com/product/redhat/enterprise_linux_workstation) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.0, 7.0
- [Jboss Enterprise Web Server](https://www.precursorintelligence.com/product/redhat/jboss_enterprise_web_server) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 2.0.0, 3.0.0
- [Linux](https://www.precursorintelligence.com/product/oracle/linux) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Operating system): 6
- [Mac OS X](https://www.precursorintelligence.com/product/apple/mac_os_x) by [Apple](https://www.precursorintelligence.com/vendors/apple) (Operating system): before 10.10.4
- [Mac OS X Server](https://www.precursorintelligence.com/product/apple/mac_os_x_server) by [Apple](https://www.precursorintelligence.com/vendors/apple) (Operating system): before 5.0.3
- [Solaris](https://www.precursorintelligence.com/product/oracle/solaris) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Operating system): 11.2

## How do I fix CVE-2013-5704?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [svn.apache.org](http://svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_http.c) (Patch, Vendor advisory)
- [svn.apache.org](http://svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_http.c?r1=1610674&r2=1610814&diff_format=h) (Patch, Vendor advisory)
- [svn.apache.org](http://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x/CHANGES) (Release notes, Vendor advisory)
- [httpd.apache.org](https://httpd.apache.org/security/vulnerabilities_24.html) (Vendor advisory)
- [lists.apple.com](http://lists.apple.com/archives/security-announce/2015/Apr/msg00001.html) (Mailing list, Third-party advisory)
- [lists.apple.com](http://lists.apple.com/archives/security-announce/2015/Sep/msg00004.html) (Mailing list, Third-party advisory)
- [marc.info](http://marc.info/?l=apache-httpd-dev&m=139636309822854&w=2) (Mailing list, Third-party advisory)
- [marc.info](http://marc.info/?l=bugtraq&m=143403519711434&w=2) (Issue tracking, Mailing list, Third-party advisory)
- [marc.info](http://marc.info/?l=bugtraq&m=144493176821532&w=2) (Issue tracking, Mailing list, Third-party advisory)
- [martin.swende.se](http://martin.swende.se/blog/HTTPChunked.html) (Broken link, Exploit, Third-party advisory)
- [rhn.redhat.com](http://rhn.redhat.com/errata/RHSA-2015-0325.html) (Third-party advisory)
- [rhn.redhat.com](http://rhn.redhat.com/errata/RHSA-2015-1249.html) (Third-party advisory)
- [rhn.redhat.com](http://rhn.redhat.com/errata/RHSA-2015-2661.html) (Broken link, Third-party advisory)
- [rhn.redhat.com](http://rhn.redhat.com/errata/RHSA-2016-0061.html) (Third-party advisory)
- [rhn.redhat.com](http://rhn.redhat.com/errata/RHSA-2016-0062.html) (Third-party advisory)
- [mandriva.com](http://www.mandriva.com/security/advisories?name=MDVSA-2014:174) (Third-party advisory)
- [oracle.com](http://www.oracle.com/technetwork/topics/security/bulletinjan2015-2370101.html) (Third-party advisory)
- [oracle.com](http://www.oracle.com/technetwork/topics/security/cpujan2015-1972971.html) (Third-party advisory)
- [oracle.com](http://www.oracle.com/technetwork/topics/security/cpujan2016-2367955.html) (Third-party advisory)
- [oracle.com](http://www.oracle.com/technetwork/topics/security/cpujul2015-2367936.html) (Third-party advisory)
- [oracle.com](http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html) (Third-party advisory)
- [securityfocus.com](http://www.securityfocus.com/bid/66550) (Third-party advisory, Vulnerability database)
- [ubuntu.com](http://www.ubuntu.com/usn/USN-2523-1) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2015:2659) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2015:2660) (Third-party advisory)
- [h20564.www2.hpe.com](https://h20564.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c04832246) (Third-party advisory)
- [lists.apache.org](https://lists.apache.org/thread.html/56c2e7cc9deb1c12a843d0dc251ea7fd3e7e80293cde02fcd65286ba%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/84a3714f0878781f6ed84473d1a503d2cc382277e100450209231830%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r83109088737656fa6307bd99ab40f8ff0269ae58d3f7272d7048494a%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r9821b0a32a1d0a1b4947abb6f3630053fcbb2ec905d9a32c2bd4d4ee%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r9ea3538f229874c80a10af473856a81fbf5f694cd7f471cc679ba70b%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/ra7f6aeb28661fbf826969526585f16856abc4615877875f9d3b35ef4%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/rcc44594d4d6579b90deccd4536b5d31f099ef563df39b094be286b9e%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/rd18c3c43602e66f9cdcf09f1de233804975b9572b0456cc582390b6f%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/rdca61ae990660bacb682295f2a09d34612b7bb5f457577fe17f4d064%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/re3d27b6250aa8548b8845d314bb8a350b3df326cacbbfdfe4d455234%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/rfbaf647d52c1cb843e726a0933f156366a806cead84fbd430951591b%40%3Ccvs.httpd.apache.org%3E)
- [security.gentoo.org](https://security.gentoo.org/glsa/201504-03) (Third-party advisory)
- [support.apple.com](https://support.apple.com/HT204659) (Third-party advisory)
- [support.apple.com](https://support.apple.com/HT205219) (Third-party advisory)

## Questions

### What is CVE-2013-5704?

CVE-2013-5704 is a medium-severity flaw in HTTP Server from Apache, published on 15 April 2014. It can be attacked from anywhere on the internet without logging in. If it works, the attacker can change some data.

### How serious is CVE-2013-5704?

It scores 5.0 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2013-5704 is 45 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

### Is CVE-2013-5704 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 53%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2013-5704 affect?

For HTTP Server from Apache: 2.2.0, 2.2.2, 2.2.3, 2.2.4, 2.2.5, 2.2.6 and 28 more. The record lists 16 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2013-5704?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2013-5704 affect you?

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- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
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