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NVD / CVE Program· CNA mozilla

CVE-2026-12304: Same-origin policy bypass in the Networking: Cookies component

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: firefox (AlmaLinux:10) 140.12.0-1.el10_2; thunderbird (AlmaLinux:10) 140.12.0-1.el10_2.alma.1; firefox (AlmaLinux:8) 140.12.0-1.el8_10.alma.1.

Low priority for now. Upgrade to firefox (AlmaLinux:10) 140.12.0-1.el10_2; thunderbird (AlmaLinux:10) 140.12.0-1.el10_2.alma.1; firefox (AlmaLinux:8) 140.12.0-1.el8_10.alma.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CriticalCVSS 9.1 · v3.1—No exploit Fix available
Published
Jun 16, 2026
Updated
Oct 26, 2026
EPSS
0.1% · 8th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-12304

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
mozillafirefox
mozillathunderbird

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • mozilla firefoxbefore 140.12.0
  • mozilla firefoxbefore 152.0.0
  • mozilla thunderbirdbefore 140.12.0
  • mozilla thunderbirdbefore 152.0.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mozilla). Independent of NVD's CPE analysis and usually ahead of it.

  • Mozilla Firefox

    • 140.12 and later · up to and including 140.*not affected · rpm
    • 152 and laternot affected · rpm

  • Mozilla Thunderbird

    • 140.12 and later · up to and including 140.*not affected · rpm
    • 152 and laternot affected · rpm

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10firefoxbefore 140.12.0-1.el10_2140.12.0-1.el10_2
AlmaLinux:10thunderbirdbefore 140.12.0-1.el10_2.alma.1140.12.0-1.el10_2.alma.1
AlmaLinux:8firefoxbefore 140.12.0-1.el8_10.alma.1140.12.0-1.el8_10.alma.1
AlmaLinux:8thunderbirdbefore 140.12.0-1.el8_10.alma.1140.12.0-1.el8_10.alma.1
AlmaLinux:9firefoxbefore 140.12.0-1.el9_8.alma.1140.12.0-1.el9_8.alma.1
AlmaLinux:9firefox-x11before 140.12.0-1.el9_8.alma.1140.12.0-1.el9_8.alma.1
AlmaLinux:9thunderbirdbefore 140.12.0-1.el9_8.alma.1140.12.0-1.el9_8.alma.1
Debian:12firefox-esrbefore 140.12.0esr-1~deb12u1140.12.0esr-1~deb12u1
Debian:12thunderbirdbefore 1:140.12.0esr-1~deb12u11:140.12.0esr-1~deb12u1
Debian:13firefox-esrbefore 140.12.0esr-1~deb13u1140.12.0esr-1~deb13u1
Debian:13thunderbirdbefore 1:140.12.0esr-1~deb13u11:140.12.0esr-1~deb13u1
Debian:14firefox-esrbefore 140.12.0esr-1140.12.0esr-1
Debian:14thunderbirdbefore 1:140.12.0esr-11:140.12.0esr-1
openSUSE:Leap 16.0MozillaFirefoxbefore 140.13.0-160000.1.1140.13.0-160000.1.1
openSUSE:Leap 16.0MozillaFirefoxbefore 140.12.0-160000.1.1140.12.0-160000.1.1
openSUSE:Leap 16.0MozillaThunderbirdbefore 140.12.0-bp160.1.1140.12.0-bp160.1.1
openSUSE:Tumbleweedfirefox-esrbefore 140.12.0-1.1140.12.0-1.1
openSUSE:TumbleweedMozillaFirefoxbefore 152.0-1.1152.0-1.1
openSUSE:TumbleweedMozillaThunderbirdbefore 140.12.0-1.1140.12.0-1.1
Red Hat:enterprise_linux_eus:10.0firefoxbefore 0:140.12.0-1.el10_00:140.12.0-1.el10_0
Red Hat:enterprise_linux_eus:10.0firefox-debuginfobefore 0:140.12.0-1.el10_00:140.12.0-1.el10_0
Red Hat:enterprise_linux_eus:10.0firefox-debugsourcebefore 0:140.12.0-1.el10_00:140.12.0-1.el10_0
Red Hat:enterprise_linux_eus:10.0thunderbirdbefore 0:140.12.0-1.el10_00:140.12.0-1.el10_0
Red Hat:enterprise_linux_eus:10.0thunderbird-debuginfobefore 0:140.12.0-1.el10_00:140.12.0-1.el10_0

+72

Same product

mozilla: all records

Other highest-scoring records for the same primary product.

  • CVE-2010-3765Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before 3.1.6 and 3.0.x before 3.0.10, and SeaMonkey 2.x…KEV
    94Now
  • CVE-2019-11708Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the…KEV
    87Now
  • CVE-2015-4495The PDF reader in Mozilla Firefox before 39.0.3, Firefox ESR 38.x before 38.1.1, and Firefox OS before 2.2 allows remote attackers to…KEV
    86Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-12302Jun 16, 2026 · Mitigation bypass in the DOM: Security component
    26Monitor
  • ← EarlierCVE-2026-12303Jun 16, 2026 · Information disclosure due to incorrect boundary conditions in the Graphics: WebGPU component
    17Monitor
  • Later →CVE-2026-12305Jun 16, 2026 · Memory safety bug fixed in Thunderbird 152
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:firefox140.12.0-1.el8_10.alma.1 · AlmaLinux:8Package registry (OSV)
almalinux:firefox-x11140.12.0-1.el9_8.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:thunderbird140.12.0-1.el9_8.alma.1 · AlmaLinux:9Package registry (OSV)
debian:firefox-esr140.12.0esr-1~deb12u1 · Debian:12Package registry (OSV)
debian:thunderbird1:140.12.0esr-1~deb12u1 · Debian:12Package registry (OSV)
opensuse:firefox-esr140.12.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:MozillaFirefox152.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:MozillaThunderbird140.12.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:firefox0:140.12.0-1.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:firefox-debuginfo0:140.12.0-1.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:firefox-debugsource0:140.12.0-1.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:firefox-x110:140.12.0-1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:thunderbird0:140.12.0-1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:thunderbird-debuginfo0:140.12.0-1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:thunderbird-debugsource0:140.12.0-1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
rocky linux:firefox0:140.12.0-1.el8_10 · Rocky Linux:8Package registry (OSV)
rocky linux:thunderbird0:140.12.0-1.el9_8 · Rocky Linux:9Package registry (OSV)
suse:MozillaFirefox140.12.0-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:MozillaThunderbird140.12.0-150200.8.277.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-1634935 days apartSame-origin policy bypass in the DOM: Navigation component
    39Monitor
  • CVE-2026-1635835 days apartSite isolation issue in the Graphics: WebRender component
    39Monitor
  • CVE-2026-1637535 days apartSite isolation issue in the Networking: HTTP component
    39Monitor
  • CVE-2026-8412977 days apartSite isolation issue in the DOM: Navigation component
    39Monitor
  • CVE-2026-8413377 days apartSite isolation issue in the DOM: Push Subscriptions component
    39Monitor
  • CVE-2026-8414077 days apartSite isolation issue in the DOM: Navigation component
    39Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-346 · Origin Validation Error

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records