UpHeron
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Servers and applications

CVE-2009-1891

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).

Severity
High 7.1
Published
10 Jul 2009
Last changed
16 Jun 2026
Added to UpHeron
17 Oct 2026
Fixed in
2.0.64, 2.2.12
Exploit chance
17% in the next 30 daysHigher than 97% of CVEs. EPSS by FIRST, 12 Nov 2026
Weakness
Uncontrolled resource consumption (CWE-400)
Attack
Over the network · No login needed
Attacker can
Take it down
CVSS vector
AV:N/AC:M/Au:N/C:N/I:N/A:C
Sources
NVD

Affected software

SoftwareAffected versions
Apache HTTP ServerServers and applications · cpe:a:apache:http_server
  • From 2.0.35 before 2.0.64
  • From 2.2.0 before 2.2.12

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2009-1891
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2009-1891