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CVE-2009-1891

31
FAUCET Score

CVE-2009-1891 describes a denial-of-service vulnerability in the mod_deflate module of Apache httpd versions 2.2.11 and earlier, affecting various distributions including Canonical, Debian, Fedora, and Red Hat. The vulnerability allows remote attackers to consume excessive CPU resources by forcing the server to continue compressing large files even after a client disconnects. With a CVSS score of 7.1, this vulnerability is considered high severity due to its network-based attack vector, medium attack complexity, and high impact on availability. There is no evidence of active exploitation, nor are there any known public exploit tools like Metasploit or ExploitDB entries, and it has received minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.0.35, < 2.0.64CPE matchmatch criteria
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
>= 2.2.0, < 2.2.12CPE matchmatch criteria
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
4.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:4.0:*:*:*:*:*:*:*
5.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:5.0:*:*:*:*:*:*:*
6.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:6.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

7.1HIGH

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

Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Exploitability Score
8.6
Impact Score
6.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
17.11%
Probability of exploitation in next 30 days
EPSS Percentile
96.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.1711 is in the 83rd percentile among its peer group of 8,920 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (26)

redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: tomcat5-0:5.5.23-0jpp_4rh.16
View patch
redhatpatch availablevia redhat_api
Product: JBEWS 1.0 for RHEL 4Fixed in: httpd22-0:2.2.10-23.1.ep5.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: ant-0:1.6.5-1jpp_1rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: avalon-logkit-0:1.2-2jpp_4rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: axis-0:1.2.1-1jpp_3rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: classpathx-jaf-0:1.0-2jpp_6rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: classpathx-mail-0:1.1.1-2jpp_8rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: geronimo-specs-0:1.0-0.M4.1jpp_10rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: jakarta-commons-modeler-0:2.0-3jpp_2rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: log4j-0:1.2.12-1jpp_1rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: mx4j-1:3.0.1-1jpp_4rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: pcsc-lite-0:1.3.3-3.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: rhpki-ca-0:7.3.0-20.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: rhpki-java-tools-0:7.3.0-10.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: rhpki-kra-0:7.3.0-14.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: rhpki-manage-0:7.3.0-19.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: rhpki-native-tools-0:7.3.0-6.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: rhpki-ocsp-0:7.3.0-13.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: rhpki-tks-0:7.3.0-13.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: xerces-j2-0:2.7.1-1jpp_1rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Certificate System 7.3Fixed in: xml-commons-0:1.3.02-2jpp_1rh
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 3Fixed in: httpd-0:2.0.46-75.ent
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: httpd-0:2.0.52-41.ent.6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: httpd-0:2.2.3-22.el5_3.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Enterprise Web Server 1 for RHEL 5Fixed in: httpd-0:2.2.10-10.ep5.el5
View patch

Vendor Advisories (1)

redhatCVE-2009-1891Low

httpd: possible temporary DoS (CPU consumption) in mod_deflate

Jun 26, 2009

References

bugs.debian.org / cgi-bin/bugreport.cgi
Exploit
lists.apple.com / archives/security-announce/2009/Nov/msg00000.html
Broken LinkMailing List
lists.opensuse.org / opensuse-security-announce/2009-10/msg00006.html
Mailing ListThird Party Advisory
marc.info
ExploitIssue TrackingMailing ListThird Party Advisory
marc.info
Issue TrackingMailing ListThird Party Advisory
marc.info
Issue TrackingMailing ListThird Party Advisory
marc.info
Issue TrackingMailing ListThird Party Advisory
osvdb.org / 55782
Broken Link
bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
secunia.com / advisories/35721
Not ApplicableVendor Advisory
secunia.com / advisories/35781
Not ApplicableVendor Advisory
secunia.com / advisories/35793
Not ApplicableVendor Advisory
secunia.com / advisories/35865
Not ApplicableVendor Advisory
secunia.com / advisories/37152
Not ApplicableVendor Advisory
secunia.com / advisories/37221
Not ApplicableVendor Advisory
security.gentoo.org / glsa/glsa-200907-04.xml
Third Party Advisory
lists.apache.org / thread.html/54a42d4b01968df1117cea77fc53d6beb931c0e05936ad02af93e9ac%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/5df9bfb86a3b054bb985a45ff9250b0332c9ecc181eec232489e7f79%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r0276683d8e1e07153fc8642618830ac0ade85b9ae0dc7b07f63bb8fc%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r2cb985de917e7da0848c440535f65a247754db8b2154a10089e4247b%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r5f9c22f9c28adbd9f00556059edc7b03a5d5bb71d4bb80257c0d34e4%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r7dd6be4dc38148704f2edafb44a8712abaa3a2be120d6c3314d55919%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r84d043c2115176958562133d96d851495d712aa49da155d81f6733be%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r8828e649175df56f1f9e3919938ac7826128525426e2748f0ab62feb%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r9e8622254184645bc963a1d47c5d47f6d5a36d6f080d8d2c43b2b142%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r9ea3538f229874c80a10af473856a81fbf5f694cd7f471cc679ba70b%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/rad01d817195e6cc871cb1d73b207ca326379a20a6e7f30febaf56d24%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/rb9c9f42dafa25d2f669dac2a536a03f2575bc5ec1be6f480618aee10%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/rc4c53a0d57b2771ecd4b965010580db355e38137c8711311ee1073a8%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/rdca61ae990660bacb682295f2a09d34612b7bb5f457577fe17f4d064%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E
lists.apache.org / thread.html/rfbaf647d52c1cb843e726a0933f156366a806cead84fbd430951591b%40%3Ccvs.httpd.apache.org%3E
oval.cisecurity.org / repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12361
Third Party Advisory
oval.cisecurity.org / repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A8632
Third Party Advisory
oval.cisecurity.org / repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9248
Third Party Advisory
rhn.redhat.com / errata/RHSA-2009-1148.html
Third Party Advisory
support.apple.com / kb/HT3937
Broken Link
redhat.com / archives/fedora-package-announce/2009-August/msg01363.html
Mailing ListThird Party Advisory
wiki.rpath.com / Advisories:rPSA-2009-0142
Broken Link
wiki.rpath.com / wiki/Advisories:rPSA-2009-0142
Broken Link
www-01.ibm.com / support/docview.wss
Third Party Advisory
www-01.ibm.com / support/docview.wss
Third Party Advisory
debian.org / security/2009/dsa-1834
Third Party Advisory
mandriva.com / security/advisories
Broken LinkPatch
redhat.com / support/errata/RHSA-2009-1156.html
Third Party Advisory
securityfocus.com / archive/1/507857/100/0/threaded
Third Party AdvisoryVDB Entry
securitytracker.com / id
Broken LinkThird Party AdvisoryVDB Entry
ubuntu.com / usn/USN-802-1
Third Party Advisory
vupen.com / english/advisories/2009/1841
Permissions RequiredVendor Advisory
vupen.com / english/advisories/2009/3184
Permissions RequiredVendor Advisory