CVE-2026-8974 json
Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151
published 2026-05-19 5 mo ago modified 2026-10-21 18 d ago also EUVD-2026-30922
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 30%
- public exploits
- 0
- none known
Summary
Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Patch / fix
- mozilla firefox 140.11.0, 151.0.0
- mozilla thunderbird 140.11, 151.0.0
- firefox-esr Debian 12 140.11.0esr-1~deb12u1
- firefox-esr Debian 13 140.11.0esr-1~deb13u1
- firefox-esr Debian 14 140.11.0esr-1
- thunderbird Debian 12 1:140.11.0esr-1~deb12u1
- thunderbird Debian 13 1:140.11.0esr-1~deb13u1
- thunderbird Debian 14 1:140.11.0esr-1
debian advisories DEBIAN-CVE-2026-8974
- thunderbird RHEL 8 140.11.0-1.el8_10
- thunderbird RHEL 10.2 140.11.0-1.el10_2
- thunderbird RHEL 9 140.11.0-1.el9_8
- firefox RHEL 8 140.11.0-1.el8_10
- firefox RHEL 9 140.11.0-1.el9_8
- firefox-x11 RHEL 9 140.11.0-1.el9_8
- firefox RHEL 10.2 140.11.0-1.el10_2
- firefox enterprise linux eus 10.0 140.11.0-1.el10_0
red hat advisories RHSA-2026:27715RHSA-2026:26629RHSA-2026:26630RHSA-2026:26606RHSA-2026:26551RHSA-2026:26539
- MozillaThunderbird openSUSE Leap 16.0 140.12.0-bp160.1.1
- MozillaFirefox openSUSE Tumbleweed 151.0.1-1.1
- MozillaThunderbird openSUSE Tumbleweed 140.11.1-1.1
- firefox-esr openSUSE Tumbleweed 140.11.0-1.1
opensuse advisories openSUSE-SU-2026:21168-1openSUSE-SU-2026:10863-1openSUSE-SU-2026:10864-1openSUSE-SU-2026:10813-1
- thunderbird AlmaLinux 8 140.11.0-1.el8_10.alma.1
- thunderbird AlmaLinux 10 140.11.0-1.el10_2.alma.1
- firefox AlmaLinux 9 140.11.0-1.el9_8.alma.1
- firefox-x11 AlmaLinux 9 140.11.0-1.el9_8.alma.1
- firefox AlmaLinux 10 140.11.0-1.el10_2
- thunderbird AlmaLinux 9 140.11.0-1.el9_8.alma.1
- firefox AlmaLinux 8 140.11.0-1.el8_10.alma.1
almalinux advisories ALSA-2026:22643ALSA-2026:22325ALSA-2026:21378ALSA-2026:21380ALSA-2026:21381ALSA-2026:21382
- thunderbird Rocky Linux 8 140.11.0-1.el8_10
- thunderbird Rocky Linux 10 140.11.0-1.el10_2
- firefox Rocky Linux 10 140.11.0-1.el10_2
- firefox Rocky Linux 9 140.11.0-1.el9_8
- thunderbird Rocky Linux 9 140.11.0-1.el9_8
- firefox Rocky Linux 8 140.11.0-1.el8_10
rocky linux advisories RLSA-2026:22643RLSA-2026:22325RLSA-2026:21380RLSA-2026:21378RLSA-2026:21381RLSA-2026:21382
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-2026-8974 updated cvss 6.1
firefox: Memory safety bugs fixed in Firefox ESR 140.11 and Firefox 151
-
Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 thunderbirdaffected: no fix planned “Out of support scope”
-
Red Hat Enterprise Linux 10 rhel10/firefox-flatpak, rhel10/thunderbird-flatpakaffected: no fix available
-
Red Hat Enterprise Linux AppStream (v. 8) firefox 140.11.0-1.el8_10, thunderbird 140.11.0-1.el8_10fixed: vendor fix RHSA-2026:21382
-
Red Hat Enterprise Linux AppStream (v. 9) firefox 140.11.0-1.el9_8, firefox-x11 140.11.0-1.el9_8, thunderbird 140.11.0-1.el9_8fixed: vendor fix RHSA-2026:21378
-
Red Hat Enterprise Linux AppStream (v. 10) firefox 140.11.0-1.el10_2, thunderbird 140.11.0-1.el10_2fixed: vendor fix RHSA-2026:21380
-
Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox 140.11.0-1.el8_4, thunderbird 140.11.0-1.el8_4fixed: vendor fix RHSA-2026:26629
-
Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox 140.11.0-1.el8_6, thunderbird 140.11.0-1.el8_6fixed: vendor fix RHSA-2026:26606
-
Red Hat Enterprise Linux AppStream E4S (v.8.8) firefox 140.11.0-1.el8_8, thunderbird 140.11.0-1.el8_8fixed: vendor fix RHSA-2026:26630
show 8 moreshow fewer
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Red Hat Enterprise Linux AppStream E4S (v.9.2) firefox 140.11.0-1.el9_2, firefox-x11 140.11.0-1.el9_2, thunderbird 140.11.0-1.el9_2fixed: vendor fix RHSA-2026:26491
-
Red Hat Enterprise Linux AppStream E4S (v.9.4) firefox 140.11.0-1.el9_4, firefox-x11 140.11.0-1.el9_4, thunderbird 140.11.0-1.el9_4fixed: vendor fix RHSA-2026:26493
-
Red Hat Enterprise Linux AppStream EUS (v. 10.0) firefox 140.11.0-1.el10_0, thunderbird 140.11.0-1.el10_0fixed: vendor fix RHSA-2026:27715
-
Red Hat Enterprise Linux AppStream EUS (v.9.6) firefox 140.11.0-1.el9_6, firefox-x11 140.11.0-1.el9_6, thunderbird 140.11.0-1.el9_6fixed: vendor fix RHSA-2026:26492
-
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) firefox 140.11.0-1.el8_4, thunderbird 140.11.0-1.el8_4fixed: vendor fix RHSA-2026:26629
-
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) firefox 140.11.0-1.el8_6, thunderbird 140.11.0-1.el8_6fixed: vendor fix RHSA-2026:26606
-
Red Hat Enterprise Linux AppStream TUS (v.8.8) firefox 140.11.0-1.el8_8, thunderbird 140.11.0-1.el8_8fixed: vendor fix RHSA-2026:26630
-
Red Hat Enterprise Linux Server (v. 7 ELS) firefox 140.11.0-1.el7_9fixed: vendor fix RHSA-2026:26551
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
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 5 mo ago
Exploit prediction
0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
Affected products
- Mozilla Firefox
- Mozilla Thunderbird
Classification
- Weakness
-
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
-
mozilla.org
/security/advisories/mfsa2026-46/
vendor-advisory
-
mozilla.org
/security/advisories/mfsa2026-48/
vendor-advisory
-
mozilla.org
/security/advisories/mfsa2026-50/
vendor-advisory
-
mozilla.org
/security/advisories/mfsa2026-51/
vendor-advisory
-
bugzilla.mozilla.org
/buglist.cgi?bug_id=1784128%2C1883230%2C1983677%2C2022390%2C2023116%2C2023657%2C2024255%2C2024418%2C2024441%2C
broken-link
Sources
- CVE List CVE-2026-8974
- NVD CVE-2026-8974
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