NVD / CVE Program· CNA mozilla

CVE-2026-7321: Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component

Noroxi assessment

Priority: Monitor (action score 38/100)

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: 0.25% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
Fixed version: firefox (AlmaLinux:10) 140.10.1-1.el10_2; thunderbird (AlmaLinux:10) 140.10.1-1.el10_2.alma.1; firefox (AlmaLinux:8) 140.10.1-1.el8_10.alma.1.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to firefox (AlmaLinux:10) 140.10.1-1.el10_2; thunderbird (AlmaLinux:10) 140.10.1-1.el10_2.alma.1; firefox (AlmaLinux:8) 140.10.1-1.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

Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, and Thunderbird 140.10.1.

CriticalCVSS 9.6 · v3.1—No exploit Fix available

Published: Apr 28, 2026
Updated: Oct 26, 2026
EPSS: 0.2% · 17th percentile
CWE: CWE-120

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 38 / 40 · 9.6 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

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

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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.

Vendor	Product	CPE
mozilla	firefox	cpe:2.3:a:mozilla:firefox
mozilla	thunderbird	cpe:2.3:a:mozilla:thunderbird

Affected versions

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

mozilla firefoxbefore 140.10.1
mozilla firefoxbefore 150.0
mozilla thunderbirdbefore 140.10.1
mozilla thunderbirdbefore 150.0

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
- 140.10.1 and later · up to and including 140.*not affected · rpm
- 150 and laternot affected · rpm
Mozilla Thunderbird
- 140.10.1 and later · up to and including 140.*not affected · rpm
- 150 and laternot affected · rpm

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
AlmaLinux:10	firefox	before 140.10.1-1.el10_2	140.10.1-1.el10_2
AlmaLinux:10	thunderbird	before 140.10.1-1.el10_2.alma.1	140.10.1-1.el10_2.alma.1
AlmaLinux:8	firefox	before 140.10.1-1.el8_10.alma.1	140.10.1-1.el8_10.alma.1
AlmaLinux:8	thunderbird	before 140.10.1-1.el8_10.alma.1	140.10.1-1.el8_10.alma.1
AlmaLinux:9	firefox	before 140.10.1-1.el9_8.alma.1	140.10.1-1.el9_8.alma.1
AlmaLinux:9	firefox-x11	before 140.10.1-1.el9_8.alma.1	140.10.1-1.el9_8.alma.1
Debian:12	firefox-esr	before 140.10.1esr-1~deb12u1	140.10.1esr-1~deb12u1
Debian:12	thunderbird	before 1:140.10.1esr-1~deb12u1	1:140.10.1esr-1~deb12u1
Debian:13	firefox-esr	before 140.10.1esr-1~deb13u1	140.10.1esr-1~deb13u1
Debian:13	thunderbird	before 1:140.10.1esr-1~deb13u1	1:140.10.1esr-1~deb13u1
Debian:14	firefox-esr	before 140.10.1esr-1	140.10.1esr-1
Debian:14	thunderbird	before 1:140.10.1esr-1	1:140.10.1esr-1
openSUSE:Tumbleweed	firefox-esr	before 140.10.1-1.1	140.10.1-1.1
openSUSE:Tumbleweed	MozillaThunderbird	before 140.10.1-1.1	140.10.1-1.1
Red Hat:enterprise_linux_eus:10.0	firefox	before 0:140.10.1-1.el10_0	0:140.10.1-1.el10_0
Red Hat:enterprise_linux_eus:10.0	firefox-debuginfo	before 0:140.10.1-1.el10_0	0:140.10.1-1.el10_0
Red Hat:enterprise_linux_eus:10.0	firefox-debugsource	before 0:140.10.1-1.el10_0	0:140.10.1-1.el10_0
Red Hat:enterprise_linux_eus:10.0	thunderbird	before 0:140.10.1-1.el10_0	0:140.10.1-1.el10_0
Red Hat:enterprise_linux_eus:10.0	thunderbird-debuginfo	before 0:140.10.1-1.el10_0	0:140.10.1-1.el10_0
Red Hat:enterprise_linux_eus:10.0	thunderbird-debugsource	before 0:140.10.1-1.el10_0	0:140.10.1-1.el10_0
Red Hat:enterprise_linux:10.2	firefox	before 0:140.10.1-1.el10_2	0:140.10.1-1.el10_2
Red Hat:enterprise_linux:10.2	firefox-debuginfo	before 0:140.10.1-1.el10_2	0:140.10.1-1.el10_2
Red Hat:enterprise_linux:10.2	firefox-debugsource	before 0:140.10.1-1.el10_2	0:140.10.1-1.el10_2
Red Hat:enterprise_linux:10.2	thunderbird	before 0:140.10.1-1.el10_2	0:140.10.1-1.el10_2

+60

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 befKEV
94Now
CVE-2019-11708Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxeKEV
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 bypassKEV
86Now

Published before and after this one in the same product

← EarlierCVE-2026-6786Apr 26, 2026 · Memory safety bugs fixed in Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150
30Monitor
← EarlierCVE-2026-7320Apr 28, 2026 · Information disclosure due to incorrect boundary conditions in the Audio/Video component
30Monitor
Later →CVE-2026-7322Apr 28, 2026 · Memory safety bugs fixed in Thunderbird ESR 140.10.1 and Thunderbird 150.0.1
29Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
almalinux:firefox	140.10.1-1.el10_2 · AlmaLinux:10	Package registry (OSV)
almalinux:firefox-x11	140.10.1-1.el9_8.alma.1 · AlmaLinux:9	Package registry (OSV)
almalinux:thunderbird	140.10.1-1.el10_2.alma.1 · AlmaLinux:10	Package registry (OSV)
debian:firefox-esr	140.10.1esr-1~deb12u1 · Debian:12	Package registry (OSV)
debian:thunderbird	1:140.10.1esr-1~deb12u1 · Debian:12	Package registry (OSV)
opensuse:firefox-esr	140.10.1-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
opensuse:MozillaThunderbird	140.10.1-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
red hat:firefox	0:140.10.1-1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:firefox-debuginfo	0:140.10.1-1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:firefox-debugsource	0:140.10.1-1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:firefox-x11	0:140.10.1-1.el9_8 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)
red hat:thunderbird	0:140.10.1-1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:thunderbird-debuginfo	0:140.10.1-1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
red hat:thunderbird-debugsource	0:140.10.1-1.el10_2 · Red Hat:enterprise_linux:10.2	Package registry (OSV)
rocky linux:firefox	0:140.10.1-1.el9_8 · Rocky Linux:9	Package registry (OSV)
rocky linux:thunderbird	0:140.10.1-1.el10_2 · Rocky Linux:10	Package 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.

The Mozilla Fuzzing Team

Variant candidates

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

CVE-2026-472035 days apartMemory safety bugs fixed in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149
39Monitor
CVE-2026-472135 days apartMemory safety bugs fixed in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149
39Monitor
CVE-2026-472935 days apartMemory safety bugs fixed in Firefox 149 and Thunderbird 149
39Monitor
CVE-2026-92006140 days apartPrivilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
35Monitor
CVE-2026-92008140 days apartPrivilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
35Monitor
CVE-2026-92010140 days apartPrivilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
35Monitor

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0129 · Apr 29, 2026(Mozilla Firefox/Thunderbird/ESR Güvenlik Bildirimi)

All national notices →

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
A user must open a link or visit a page.
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: high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Changed
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

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

nvd-secondary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1char buf[256];
2memcpy(buf, pkt->data, pkt->len);

Fixed

1char buf[256];
2if (pkt->len > sizeof(buf)) {
3  return -EINVAL;
4}
5memcpy(buf, pkt->data, pkt->len);

Attack context

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

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

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

References

bugzilla.mozilla.org/show_bug.cgi?id=2029461

Show all references (4 more)

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

All records