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CVE-2009-1836

20
FAUCET Score

CVE-2009-1836 describes a vulnerability in older versions of Mozilla Firefox, Thunderbird, and SeaMonkey where the HTTP Host header was improperly used to determine the context of a document from a proxy server's non-200 CONNECT response. This flaw allowed man-in-the-middle attackers to execute arbitrary web script through "SSL tampering." The vulnerability has a CVSS score of 6.8, indicating a medium severity, with a network attack vector, medium attack complexity, and potential for partial impact on confidentiality, integrity, and availability. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 3.0.10CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
0.1CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:0.1:*:*:*:*:*:*:*
0.2CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:0.2:*:*:*:*:*:*:*
0.3CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:0.3:*:*:*:*:*:*:*
0.4CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:0.4:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

6.8MEDIUM

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

Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Exploitability Score
8.6
Impact Score
6.4
CvssVersion
2.0

Exploit Intelligence

EPSS Score
2.03%
Probability of exploitation in next 30 days
EPSS Percentile
79.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0203 is in the 64th percentile among its peer group of 19,958 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Patch Available

Vendor Patches (5)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: firefox-0:3.0.11-4.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: firefox-0:3.0.11-2.el5_3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: xulrunner-0:1.9.0.11-3.el5_3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: thunderbird-0:2.0.0.22-2.el5_3
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2009-1836Moderate

Firefox SSL tampering via non-200 responses to proxy CONNECT requests

Jun 11, 2009

References

osvdb.org / 55160
research.microsoft.com / apps/pubs/default.aspx
research.microsoft.com / pubs/79323/pbp-final-with-update.pdf
bugzilla.mozilla.org / show_bug.cgi
Exploit
bugzilla.redhat.com / show_bug.cgi
Exploit
secunia.com / advisories/35331
Vendor Advisory
secunia.com / advisories/35415
secunia.com / advisories/35431
Vendor Advisory
secunia.com / advisories/35439
Vendor Advisory
secunia.com / advisories/35440
Vendor Advisory
secunia.com / advisories/35468
secunia.com / advisories/35536
secunia.com / advisories/35561
secunia.com / advisories/35602
secunia.com / advisories/35882
slackware.com / security/viewer.php
slackware.com / security/viewer.php
oval.cisecurity.org / repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11764
rhn.redhat.com / errata/RHSA-2009-1095.html
Patch
sunsolve.sun.com / search/document.do
redhat.com / archives/fedora-package-announce/2009-July/msg00444.html
redhat.com / archives/fedora-package-announce/2009-July/msg00504.html
redhat.com / archives/fedora-package-announce/2009-June/msg00574.html
redhat.com / archives/fedora-package-announce/2009-June/msg00657.html
debian.org / security/2009/dsa-1820
debian.org / security/2009/dsa-1830
mandriva.com / security/advisories
mozilla.org / security/announce/2009/mfsa2009-27.html
Vendor Advisory
redhat.com / support/errata/RHSA-2009-1126.html
securityfocus.com / bid/35326
securityfocus.com / bid/35380
securitytracker.com / id
slackware.com / security/viewer.php
ubuntu.com / usn/usn-782-1
vupen.com / english/advisories/2009/1572
PatchVendor Advisory