CVE-2026-2796

JIT miscompilation in the JavaScript: WebAssembly component

9.8 CriticalPublic exploit

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.95%Up 0.9 points since Feb 25, 2026

What each source reports

NVD Score used9.8

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Record: CVE-2026-2796
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-843
Updated: 2026-11-02

CVE List9.8

JIT miscompilation in the JavaScript: WebAssembly component

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Record: CVE-2026-2796
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-843
Updated: 2026-11-02

EUVDEUVD-2026-84499.8

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Record: EUVD-2026-8449
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-c3q8-4689-m4p69.8

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability affects Firefox <...

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability affects Firefox < 148.

Record: GHSA-c3q8-4689-m4p6
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-843
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-27969.8

JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Record: UBUNTU-CVE-2026-2796
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVopenSUSE-SU-2026:10257-1No score

MozillaFirefox-148.0-1.1 on GA media

These are all security issues fixed in the MozillaFirefox-148.0-1.1 package on the GA media of openSUSE Tumbleweed.

Record: openSUSE-SU-2026:10257-1
Updated: 2026-11-02

OSVopenSUSE-SU-2026:11373-1No score

firefox-esr-153.0-1.1 on GA media

These are all security issues fixed in the firefox-esr-153.0-1.1 package on the GA media of openSUSE Tumbleweed.

Record: openSUSE-SU-2026:11373-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`mozjs52` Ubuntu:18.04:LTS	All versions, plus listed versions 52.3.1-0ubuntu352.3.1-7fakesync152.8.1-0ubuntu0.18.04.152.9.1-0ubuntu0.18.04.1	None known
`mozjs38` Ubuntu:18.04:LTS	All versions, plus listed versions 38.8.0~repack1-0ubuntu138.8.0~repack1-0ubuntu338.8.0~repack1-0ubuntu4	None known
`mozjs68` Ubuntu:20.04:LTS	All versions, plus listed versions 68.5.0-1~fakesync68.5.0-2~fakesync68.6.0-168.6.0-1ubuntu1	None known
`mozjs52` Ubuntu:20.04:LTS	All versions, plus listed versions 52.9.1-1build152.9.1-1ubuntu3	None known
`mozjs102` Ubuntu:22.04:LTS	All versions, plus listed versions 102.11.0-0ubuntu0.22.04.1102.12.0-0ubuntu0.22.04.1102.13.0-0ubuntu0.22.04.1102.15.1-0ubuntu0.22.04.1	None known
`mozjs78` Ubuntu:22.04:LTS	All versions, plus listed versions 78.13.0-178.15.0-278.15.0-4ubuntu1	None known
`mozjs91` Ubuntu:22.04:LTS	All versions, plus listed versions 91.5.1-0ubuntu191.6.0-191.6.0-291.7.0-291.10.0-0ubuntu1	None known
`thunderbird` Ubuntu:22.04:LTS	All versions, plus listed versions 1:91.1.2+build1-0ubuntu11:91.3.0+build2-0ubuntu11:91.3.1+build1-0ubuntu11:91.3.2+build1-0ubuntu11:91.4.0+build1.1-0ubuntu1 Show 34 moreShow less 1:91.4.0+build2-0ubuntu11:91.5.0+build1-0ubuntu11:91.5.1+build1-0ubuntu11:91.6.1+build1-0ubuntu11:91.7.0+build1-0ubuntu11:91.7.0+build2-0ubuntu11:91.8.0+build2-0ubuntu11:91.9.1+build1-0ubuntu0.22.04.11:91.11.0+build2-0ubuntu0.22.04.11:102.2.2+build1-0ubuntu0.22.04.11:102.4.2+build2-0ubuntu0.22.04.11:102.7.1+build2-0ubuntu0.22.04.11:102.8.0+build2-0ubuntu0.22.04.11:102.9.0+build1-0ubuntu0.22.04.11:102.10.0+build2-0ubuntu0.22.04.11:102.11.0+build1-0ubuntu0.22.04.11:102.13.0+build1-0ubuntu0.22.04.11:102.15.0+build1-0ubuntu0.22.04.11:102.15.1+build1-0ubuntu0.22.04.11:115.3.1+build1-0ubuntu0.22.04.21:115.4.1+build1-0ubuntu0.22.04.11:115.5.0+build1-0ubuntu0.22.04.11:115.6.0+build2-0ubuntu0.22.04.11:115.8.1+build1-0ubuntu0.22.04.11:115.9.0+build1-0ubuntu0.22.04.11:115.10.1+build1-0ubuntu0.22.04.11:115.11.0+build2-0ubuntu0.22.04.11:115.12.0+build3-0ubuntu0.22.04.11:115.13.0+build5-0ubuntu0.22.04.11:115.15.0+build1-0ubuntu0.22.04.11:115.16.0+build2-0ubuntu0.22.04.11:115.18.0+build1-0ubuntu0.22.04.11:128.12.0+build1-0ubuntu0.22.04.11:140.7.1+build1-0ubuntu0.22.04.1	None known
`mozjs102` Ubuntu:24.04:LTS	All versions, plus listed versions 102.15.1-1102.15.1-3ubuntu2	None known
`mozjs115` Ubuntu:24.04:LTS	All versions, plus listed versions 115.3.0-0ubuntu1115.4.0-2115.5.0-1115.6.0-1115.7.0-4 Show 4 moreShow less 115.8.0-1115.9.0-1115.9.0-1build1115.10.0-1	None known
`MozillaFirefox` openSUSE:Tumbleweed From an advisory covering 51 CVEs	before 148.0-1.1	148.0-1.1
`firefox-esr` openSUSE:Tumbleweed From an advisory covering 228 CVEs	before 153.0-1.1	153.0-1.1

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
Source	Link	Date
PoC in GitHub	WostGit/CVE-2026-2796	2026-04-09
PoC in GitHub	WostGit/cve-2026-2796-repro	2026-04-09
PoC in GitHub	SneakyNachos/CVE-2026-2796-and-CVE-2026-2768-escape-the-wasm-box	2026-08-20
PoC in GitHub	SneakyNachos/CVE-2026-2796-escape-wasm-by-using-wasm	2026-08-20

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, exploits, facts
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-2796 is a critical vulnerability (CVSS 9.8) in Mozilla Firefox, published February 24, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 0.95%, the 61st percentile. No source names a fixed version.

References

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