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Vulnerability record · CVE-2009-1891 · published 10 July 2009

CVE-2009-1891: Apache http server uncontrolled resource consumption vulnerability

Apache · Http Server

The mod_deflate module in Apache httpd 2.2.11 and earlier compresses large files until completion even after the associated network connection is closed, which allows remote attackers to cause a denial of service (CPU consumption).

7.1 CVSS 2.0 High EPSS 17% · top 3.0% CWE-400 · Uncontrolled resource consumption
7.1CVSS 2.0 base score
17%EPSS exploitation probability, 30 days
NoNot in CISA KEV
9Affected product versions listed by NVD
110References, 4 tagged exploit
16 Jun 2026Last modified by NVD

Description

The mod_deflate module in Apache httpd 2.2.11 and earlier compresses large files until completion even after the associated network connection is closed, which allows remote attackers to cause a denial of service (CPU consumption).

AV:N/AC:M/Au:N/C:N/I:N/A:C

Affected products

9 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=534712 Exploit
http://lists.apple.com/archives/security-announce/2009/Nov/msg00000.html Broken LinkMailing List
http://lists.opensuse.org/opensuse-security-announce/2009-10/msg00006.html Mailing ListThird Party Advisory
http://marc.info/?l=apache-httpd-dev&m=124621326524824&w=2 ExploitIssue TrackingMailing ListThird Party Advisory
http://marc.info/?l=apache-httpd-dev&m=124661528519546&w=2 Issue TrackingMailing ListThird Party Advisory
http://marc.info/?l=bugtraq&m=129190899612998&w=2 Issue TrackingMailing ListThird Party Advisory
http://marc.info/?l=bugtraq&m=130497311408250&w=2 Issue TrackingMailing ListThird Party Advisory
http://osvdb.org/55782 Broken Link
http://secunia.com/advisories/35721 Not ApplicableVendor Advisory
http://secunia.com/advisories/35781 Not ApplicableVendor Advisory
http://secunia.com/advisories/35793 Not ApplicableVendor Advisory
http://secunia.com/advisories/35865 Not ApplicableVendor Advisory
http://secunia.com/advisories/37152 Not ApplicableVendor Advisory
http://secunia.com/advisories/37221 Not ApplicableVendor Advisory
http://security.gentoo.org/glsa/glsa-200907-04.xml Third Party Advisory
http://support.apple.com/kb/HT3937 Broken Link
http://wiki.rpath.com/Advisories:rPSA-2009-0142 Broken Link
http://wiki.rpath.com/wiki/Advisories:rPSA-2009-0142 Broken Link
http://www-01.ibm.com/support/docview.wss?uid=swg1PK91361 Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg1PK99480 Third Party Advisory
http://www.debian.org/security/2009/dsa-1834 Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:149 Broken LinkPatch
http://www.redhat.com/support/errata/RHSA-2009-1156.html Third Party Advisory
http://www.securityfocus.com/archive/1/507857/100/0/threaded Third Party AdvisoryVDB Entry
http://www.securitytracker.com/id?1022529 Broken LinkThird Party AdvisoryVDB Entry
http://www.ubuntu.com/usn/USN-802-1 Third Party Advisory
http://www.vupen.com/english/advisories/2009/1841 Permissions RequiredVendor Advisory
http://www.vupen.com/english/advisories/2009/3184 Permissions RequiredVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=509125 Issue TrackingPatchThird Party Advisory
https://lists.apache.org/thread.html/54a42d4b01968df1117cea77fc53d6beb931c0e05936ad02af93e9ac%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/5df9bfb86a3b054bb985a45ff9250b0332c9ecc181eec232489e7f79%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/r0276683d8e1e07153fc8642618830ac0ade85b9ae0dc7b07f63bb8fc%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r2cb985de917e7da0848c440535f65a247754db8b2154a10089e4247b%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r5f9c22f9c28adbd9f00556059edc7b03a5d5bb71d4bb80257c0d34e4%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r7dd6be4dc38148704f2edafb44a8712abaa3a2be120d6c3314d55919%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r84d043c2115176958562133d96d851495d712aa49da155d81f6733be%40%3Ccvs.httpd.apache.org

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Source: NIST National Vulnerability Database (record CVE-2009-1891), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.