CVE-2026-6786

HIGH EPSS 29.6%
Published Apr 26, 20262mo ago · Modified Jun 17, 20261w ago
7.5 CVSS 3.1
High
Find Similar
Published Apr 26, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

Description

Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. 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 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

CVSS Details

Base Score
7.5
Exploitability
1.6
Impact
5.9
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
29.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 3

CWE-125 Out-of-bounds Read Memory Safety
CWE-416 Use After Free Memory Safety
CWE-787 Out-of-bounds Write Memory Safety

Affected Products 3

VendorProductVersionRange
mozillafirefox* <150.0
mozillafirefox*≥140.0  –  <140.10.0
mozillathunderbird*≥140.0  –  <140.10.0

References 5

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/buglist.cgi?bug_id=2010727%2C2019004%2C2019224%2C2019547%2C2020378%2C2022381%2C2022608%2C2022785%2C2023120%2C2023128%2C2023140%2C2023279%2C2023836%2C2023882%2C2023925%2C2023950%2C2023959%2C2023965%2C2024243%2C2024245%2C2024247%2C2024253%2C2024346%2C2024357%2C2024416%2C2024420%2C2024429%2C2024432%2C2024455%2C2024466%2C2024468%2C2024476%2C2024664%2C2024666%2C2024669%2C2024670%2C2024671%2C2024761%2C2024918%2C2025292%2C2025332%2C2025348%2C2025384%2C2025395%2C2025458%2C2025461%2C2025463%2C2025481%2C2025483%2C2025485%2C2025494%2C2025506%2C2025511%2C2025513%2C2025520%2C2026277%2C2026282%2C2026288%2C2026289%2C2026311%2C2026312%2C2026869%2C2027152%2C2027161%2C2027238%2C2027261%2C2027269%2C2027274%2C2027280%2C2027281%2C2027300%2C2027302%2C2027331%2C2027339%2C2027340%2C2027738%2C2027975%2C2028000%2C2028011%2C2028289%2C2028525%2C2028728%2C2028887%2C2028888%2C2028896%2C2029063%2C2029064%2C2029290%2C2029291%2C2029294%2C2029300%2C2029304%2C2029316%2C2029317%2C2029401%2C2029415%2C2029430%2C2029457%2C2029727%2C2029735%2C2029743%2C2029752%2C2029754%2C2029776%2C2029809%2C2030324%2C2030370
    Broken Link
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2026-30/
    Vendor Advisory
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2026-32/
    Vendor Advisory
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2026-33/
    Vendor Advisory
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2026-34/
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.