CVE-2026-4700 — Authentication Bypass Using an Alternate Path or Channel in Mozilla Firefox

CWE-288 — Authentication Bypass Using an Alternate Path or ChannelCWE-444 — HTTP Request Smuggling13 documents10 sources
Severity
9.8CRITICALNVD
EPSS
0.0%
top 94.09%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla ThunderbirdMozilla Firefox
Timeline
PublishedMar 24
Latest updateApr 16

Description

Mitigation bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitability: 3.9 | Impact: 5.9

Affected Packages2 packages

▶NVDmozilla/firefox< 140.9.0+1
▶Debianmozilla/thunderbird< 1:140.9.0esr-1~deb11u1+3

🔴Vulnerability Details

4
VulDB
Mozilla Firefox up to 148 HTTP (Nessus ID 303907 / WID-SEC-2026-0850)↗2026-04-16
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GHSA
GHSA-4pf4-jp4v-4g5c: Mitigation bypass in the Networking: HTTP component↗2026-03-24
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OSV
CVE-2026-4700: Mitigation bypass in the Networking: HTTP component↗2026-03-24
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CVEList
Mitigation bypass in the Networking: HTTP component↗2026-03-24
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📋Vendor Advisories

6
Red Hat
firefox: thunderbird: Mitigation bypass in the Networking: HTTP component↗2026-03-24
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Debian
CVE-2026-4700: firefox - Mitigation bypass in the Networking: HTTP component. This vulnerability affects ...↗2026
▶
Mozilla
Mozilla Foundation Security Advisory 2026-23: CVE-2026-4700↗
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Mozilla
Mozilla Foundation Security Advisory 2026-24: CVE-2026-4700↗
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Mozilla
Mozilla Foundation Security Advisory 2026-22: CVE-2026-4700↗
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🕵️Threat Intelligence

1
Wiz
CVE-2026-4700 Impact, Exploitability, and Mitigation Steps | Wiz↗
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💬Community

1
Bugzilla
CVE-2026-4700 firefox: thunderbird: Mitigation bypass in the Networking: HTTP component↗2026-03-24
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CVE-2026-4700 — Mozilla Firefox vulnerability | cvebase