CVE-2026-12290 | Memory safety bug fixed in Firefox 152

Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

Published: 2026-06-16 Last update: 2026-06-30 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-12290 is rated Moderate Risk (43.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.40%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-12290

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-30 0.29% 0.40% +0.10%
2 2026-06-18 0.16% 0.29% +0.14%
3 2026-06-17 — 0.16% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-12290

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 5.2 134c704f-9b21-4f2e-91b3-4a467353bcc0
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 5.9 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Weakness enumeration for CVE-2026-12290

GitHub Security Advisory for CVE-2026-12290

GHSA-g3gr-6w94-3656 · Severity: high — Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152, Firefox ESR...

OS Trackers for CVE-2026-12290

vendor priority summary link
debian not yet assigned CVE-2026-12290 not yet assigned priority: Debian including 3 source packages (firefox, firefox-esr, thunderbird), 11 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 11. https://security-tracker.debian.org/tracker/CVE-2026-12290
suse critical — https://www.suse.com/security/cve/CVE-2026-12290/
ubuntu medium CVE-2026-12290 medium priority: Ubuntu including 9 source packages (firefox, mozjs102, …), 49 status rows across 7 suites (bionic, focal, jammy, noble, questing, resolute, upstream): DNE 23, needs-triage 10, ignored 8, not-affected 7, needed 1. https://ubuntu.com/security/CVE-2026-12290

Affected software / configurations for CVE-2026-12290

Vendor Product Version Raw CPE
mozilla firefox < 115.37.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
mozilla firefox < 152.0.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
mozilla firefox >= 140.0, < 140.12.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
mozilla thunderbird < 152.0.0 cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
mozilla thunderbird >= 140.0, < 140.12.0 cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*

References for CVE-2026-12290

URL Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=2024852 Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-57/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-58/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-59/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-60/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-61/ Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:27717
https://access.redhat.com/errata/RHSA-2026:27733
https://access.redhat.com/errata/RHSA-2026:27734
https://access.redhat.com/errata/RHSA-2026:29940
https://access.redhat.com/errata/RHSA-2026:30846
https://access.redhat.com/errata/RHSA-2026:33445
https://access.redhat.com/security/cve/CVE-2026-12290
https://bugzilla.redhat.com/show_bug.cgi?id=2489210
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12290.json
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