CVE-2026-8963
Spoofing issue in the Web Speech component
7.5 High
Spoofing issue in the Web Speech component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
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
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
0.30%Up 0.3 points since May 20, 2026
What each source reports
CVE List Score used
Spoofing issue in the Web Speech component
Spoofing issue in the Web Speech component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
- Record
CVE-2026-8963- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-290
- Updated
- 2026-11-02
EUVDEUVD-2026-30914
Spoofing issue in the Web Speech component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
- Record
EUVD-2026-30914- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-7f47-q24v-32rc
Spoofing issue in the Web Speech component. This vulnerability was fixed in Firefox 151.
Spoofing issue in the Web Speech component. This vulnerability was fixed in Firefox 151.
- Record
GHSA-7f47-q24v-32rc- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-290
- Updated
- 2026-11-02
NVD
Spoofing issue in the Web Speech component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
- Record
CVE-2026-8963- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-290
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-8963
Spoofing issue in the Web Speech component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
- Record
UBUNTU-CVE-2026-8963- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVCLSA-2026-1781204847 No score
thunderbird: Fix of 7 CVEs
- CVE-2026-6757: invalid pointer in wasm debug frames; add DebugEnvironments::onPopWasm to clean up the debug environment on pop
- CVE-2026-6761: privilege escalation; enforce prefs for dom TCP and UDP sockets at the parent-process IPC entry points
- CVE-2026-6764: out-of-bounds read; validate HID report length in Dualshock4Remapper::ProcessTouchData
- CVE-2026-6771: CSP 'strict-dynamic' mitigation bypass; treat XSLT as parser-created so 'strict-dynamic' no longer auto-allows it
- CVE-2026-8963: Web Speech spoofing; cancel SpeechSynthesis on navigation by overriding DisconnectFromOwner
- CVE-2026-8965: information disclosure; pass the right sanitization kind through SanitizeInlineStyle (conditional CSS)
- CVE-2026-8971: Networking JAR same-origin bypass; reject jar entry names containing an embedded NUL
- Record
CLSA-2026-1781204847- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:10863-1 No score
MozillaFirefox-151.0.1-1.1 on GA media
These are all security issues fixed in the MozillaFirefox-151.0.1-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:10863-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:11373-1 No 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
| Package | Affected | Fixed |
|---|---|---|
thunderbirdTuxCare:AlmaLinux:9.2 From an advisory covering 7 CVEs |
before 115.4.1-1.el9_2.alma.tuxcare.els7 | 115.4.1-1.el9_2.alma.tuxcare.els7 |
mozjs52Ubuntu: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 |
mozjs38Ubuntu:18.04:LTS |
All versions, plus listed versions 38.8.0~repack1-0ubuntu138.8.0~repack1-0ubuntu338.8.0~repack1-0ubuntu4 |
None known |
mozjs68Ubuntu: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 |
mozjs52Ubuntu:20.04:LTS |
All versions, plus listed versions 52.9.1-1build152.9.1-1ubuntu3 |
None known |
mozjs102Ubuntu: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 |
mozjs78Ubuntu:22.04:LTS |
All versions, plus listed versions 78.13.0-178.15.0-278.15.0-4ubuntu1 |
None known |
mozjs91Ubuntu: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 |
thunderbirdUbuntu: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 less1:91.4.0+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 |
mozjs102Ubuntu:24.04:LTS |
All versions, plus listed versions 102.15.1-1102.15.1-3ubuntu2 |
None known |
mozjs115Ubuntu: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 less115.8.0-1115.9.0-1115.9.0-1build1115.10.0-1 |
None known |
MozillaFirefoxopenSUSE:Tumbleweed From an advisory covering 31 CVEs |
before 151.0.1-1.1 | 151.0.1-1.1 |
firefox-esropenSUSE:Tumbleweed From an advisory covering 228 CVEs |
before 153.0-1.1 | 153.0-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-8963 is a high vulnerability (CVSS 7.5) in Mozilla Firefox, published May 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 23rd percentile. No source names a fixed version.
References
bugzilla.mozilla.org/show_bug.cgi?id=2021222
mozilla.org/security/advisories/mfsa2026-46
nvd.nist.gov/vuln/detail/CVE-2026-8963
github.com/advisories/GHSA-7f47-q24v-32rc
errata.tuxcare.com/els_os/almalinux9.2esu/CLSA-2026-1781204847.html
Show 194 moreShow less
ubuntu.com/security/CVE-2026-8963
cve.org/CVERecord?id=CVE-2026-8963
suse.com/security/cve/CVE-2026-8945
This page doesn't list everything
Left out here: 60 references. The JSON record has them.