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Fencer Vulns
low 2.6

CVE-2006-2786 json

HTTP response smuggling vulnerability in Mozilla Firefox and Thunderbird before 1.5.0.4, when used with certain proxy servers, allows remot…

published 2006-06-02 20 y ago modified 2026-06-16 4 mo ago also EUVD-2006-2783

cvss
2.6
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

HTTP response smuggling vulnerability in Mozilla Firefox and Thunderbird before 1.5.0.4, when used with certain proxy servers, allows remote attackers to cause Firefox to interpret certain responses as if they were responses from two different sites via (1) invalid HTTP response headers with spaces between the header name and the colon, which might not be ignored in some cases, or (2) HTTP 1.1 headers through an HTTP 1.0 proxy, which are ignored by the proxy but processed by the client.

Patch / fix

  • thunderbird Debian 14, Debian 13, Debian 12 1.5.0.4-1

debian advisories DEBIAN-CVE-2006-2786

  • thunderbird RHEL 4 1.5.0.5-0.el4.1
  • firefox RHEL 4 1.5.0.5-0.el4.1
  • seamonkey RHEL 4 1.0.3-0.el4.1
  • devhelp RHEL 4 0.10-0.2.el4
  • seamonkey-chat RHEL 4 1.0.3-0.el4.1
  • seamonkey-mail RHEL 4 1.0.3-0.el4.1
  • seamonkey-js-debugger RHEL 4 1.0.3-0.el4.1
  • seamonkey-dom-inspector RHEL 4 1.0.3-0.el4.1

red hat advisories RHSA-2006:0611RHSA-2006:0610RHSA-2006:0609RHSA-2006:0578

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2006-2786 updated

security flaw

  • Red Hat Desktop version 3 seamonkey 1.0.2-0.1.0.EL3, seamonkey-nss 1.0.2-0.1.0.EL3, seamonkey-chat 1.0.2-0.1.0.EL3, seamonkey-mail 1.0.2-0.1.0.EL3, seamonkey-nspr 1.0.2-0.1.0.EL3, seamonkey-js-debugger 1.0.2-0.1.0.EL3, +1 more Red Hat Enterprise Linux AS version 3 seamonkey 1.0.2-0.1.0.EL3, seamonkey-nss 1.0.2-0.1.0.EL3, seamonkey-chat 1.0.2-0.1.0.EL3, seamonkey-mail 1.0.2-0.1.0.EL3, seamonkey-nspr 1.0.2-0.1.0.EL3, seamonkey-js-debugger 1.0.2-0.1.0.EL3, +1 more
    fixed: vendor fix RHSA-2006:0578
  • Red Hat Enterprise Linux AS version 4 devhelp 0.10-0.2.el4, firefox 1.5.0.5-0.el4.1, seamonkey 1.0.3-0.el4.1, thunderbird 1.5.0.5-0.el4.1, seamonkey-chat 1.0.3-0.el4.1, seamonkey-mail 1.0.3-0.el4.1, +2 more Red Hat Enterprise Linux Desktop version 4 devhelp 0.10-0.2.el4, firefox 1.5.0.5-0.el4.1, seamonkey 1.0.3-0.el4.1, thunderbird 1.5.0.5-0.el4.1, seamonkey-chat 1.0.3-0.el4.1, seamonkey-mail 1.0.3-0.el4.1, +2 more
    fixed: vendor fix RHSA-2006:0609
  • Red Hat Enterprise Linux ES version 2.1
    fixed: vendor fix RHSA-2006:0594
  • Red Hat Enterprise Linux ES version 3 seamonkey 1.0.2-0.1.0.EL3, seamonkey-nss 1.0.2-0.1.0.EL3, seamonkey-chat 1.0.2-0.1.0.EL3, seamonkey-mail 1.0.2-0.1.0.EL3, seamonkey-nspr 1.0.2-0.1.0.EL3, seamonkey-js-debugger 1.0.2-0.1.0.EL3, +1 more
    fixed: vendor fix RHSA-2006:0578
  • Red Hat Enterprise Linux ES version 4 devhelp 0.10-0.2.el4, firefox 1.5.0.5-0.el4.1, seamonkey 1.0.3-0.el4.1, thunderbird 1.5.0.5-0.el4.1, seamonkey-chat 1.0.3-0.el4.1, seamonkey-mail 1.0.3-0.el4.1, +2 more
    fixed: vendor fix RHSA-2006:0609
  • Red Hat Enterprise Linux WS version 2.1
    fixed: vendor fix RHSA-2006:0594
  • Red Hat Enterprise Linux WS version 3 seamonkey 1.0.2-0.1.0.EL3, seamonkey-nss 1.0.2-0.1.0.EL3, seamonkey-chat 1.0.2-0.1.0.EL3, seamonkey-mail 1.0.2-0.1.0.EL3, seamonkey-nspr 1.0.2-0.1.0.EL3, seamonkey-js-debugger 1.0.2-0.1.0.EL3, +1 more
    fixed: vendor fix RHSA-2006:0578
  • Red Hat Enterprise Linux WS version 4 devhelp 0.10-0.2.el4, firefox 1.5.0.5-0.el4.1, seamonkey 1.0.3-0.el4.1, thunderbird 1.5.0.5-0.el4.1, seamonkey-chat 1.0.3-0.el4.1, seamonkey-mail 1.0.3-0.el4.1, +2 more
    fixed: vendor fix RHSA-2006:0609
show 1 more
  • Red Hat Linux Advanced Workstation 2.1
    fixed: vendor fix RHSA-2006:0594

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.77% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 2.6 AV:N/AC:H/Au:N/C:N/I:P/A:N

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.