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CVE-2026-92012· NVD / CVE Program· CNA mozilla

Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component

Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Sep 15, 2026
Updated
Sep 16, 2026
EPSS
0.3% · 18th percentile
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JSON

Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Affected systems

—

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

    • 115.41 and later · up to and including 115.*not affected · rpm
    • 140.16 and later · up to and including 140.*not affected · rpm
    • 153.3 and later · up to and including 153.*not affected · rpm
    • 156 and laternot affected · rpm
  • Mozilla Thunderbird

    • 140.16 and later · up to and including 140.*not affected · rpm
    • 153.3 and later · up to and including 153.*not affected · rpm
    • 156 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 140.16.0-1.el10_2140.16.0-1.el10_2
AlmaLinux:8firefoxbefore 140.16.0-1.el8_10.alma.1140.16.0-1.el8_10.alma.1
Debian:12firefox-esrbefore 140.16.0esr-1~deb12u1140.16.0esr-1~deb12u1
Debian:12thunderbirdbefore 1:140.16.0esr-1~deb12u11:140.16.0esr-1~deb12u1
Debian:13firefox-esrbefore 140.16.0esr-1~deb13u1140.16.0esr-1~deb13u1
Debian:13thunderbirdbefore 1:140.16.0esr-1~deb13u11:140.16.0esr-1~deb13u1
Debian:14firefox-esrbefore 140.16.0esr-1140.16.0esr-1
Debian:14thunderbirdall versions—
openSUSE:Leap 16.0MozillaFirefoxbefore 153.3.0-160000.1.1153.3.0-160000.1.1
openSUSE:Tumbleweedfirefox-esrbefore 153.3.0-1.1153.3.0-1.1
openSUSE:TumbleweedMozillaFirefoxbefore 156.0-1.1156.0-1.1
openSUSE:TumbleweedMozillaThunderbirdbefore 140.16.0-1.1140.16.0-1.1
Red Hat:enterprise_linux:10.2firefoxbefore 0:140.16.0-1.el10_20:140.16.0-1.el10_2
Red Hat:enterprise_linux:10.2firefox-debuginfobefore 0:140.16.0-1.el10_20:140.16.0-1.el10_2
Red Hat:enterprise_linux:10.2firefox-debugsourcebefore 0:140.16.0-1.el10_20:140.16.0-1.el10_2
Red Hat:enterprise_linux:8::appstreamfirefoxbefore 0:140.16.0-1.el8_100:140.16.0-1.el8_10
Red Hat:enterprise_linux:8::appstreamfirefox-debuginfobefore 0:140.16.0-1.el8_100:140.16.0-1.el8_10
Red Hat:enterprise_linux:8::appstreamfirefox-debugsourcebefore 0:140.16.0-1.el8_100:140.16.0-1.el8_10
Red Hat:enterprise_linux:9::appstreamfirefoxbefore 0:140.16.0-1.el9_80:140.16.0-1.el9_8
Red Hat:enterprise_linux:9::appstreamfirefox-debuginfobefore 0:140.16.0-1.el9_80:140.16.0-1.el9_8
Red Hat:enterprise_linux:9::appstreamfirefox-debugsourcebefore 0:140.16.0-1.el9_80:140.16.0-1.el9_8
Red Hat:enterprise_linux:9::appstreamfirefox-x11before 0:140.16.0-1.el9_80:140.16.0-1.el9_8
Rocky Linux:10firefoxbefore 0:140.16.0-1.el10_20:140.16.0-1.el10_2
Rocky Linux:8firefoxbefore 0:140.16.0-1.el8_100:140.16.0-1.el8_10

+3

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
  • CVE-2013-1690Mozilla Firefox before 22.0, Firefox ESR 17.x before 17.0.7, Thunderbird before 17.0.7, and Thunderbird ESR 17.x before 17.0.7 do not properKEV
    86Now
  • CVE-2019-17026Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion.KEV
    79This week
  • CVE-2024-9680An attacker was able to achieve code execution in the content process by exploiting a use-after-free in Animation timelines.KEV
    76This week

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:firefox140.16.0-1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:firefox-esr140.16.0esr-1~deb12u1 · Debian:12Package registry (OSV)
debian:thunderbird1:140.16.0esr-1~deb12u1 · Debian:12Package registry (OSV)
opensuse:firefox-esr153.3.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:MozillaFirefox156.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:MozillaThunderbird140.16.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:firefox0:140.16.0-1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:firefox-debuginfo0:140.16.0-1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:firefox-debugsource0:140.16.0-1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:firefox-x110:140.16.0-1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
rocky linux:firefox0:140.16.0-1.el10_2 · Rocky Linux:10Package registry (OSV)
suse:MozillaFirefox153.3.0-118.8.1 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.

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-2026-4720175 days apartMemory safety bugs fixed in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149
    39Monitor
  • CVE-2026-4721175 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-2026-4729175 days apartMemory safety bugs fixed in Firefox 149 and Thunderbird 149
    39Monitor
  • CVE-2026-7321140 days apartSandbox escape due to incorrect boundary conditions in the WebRTC: Networking component
    38Monitor
  • CVE-2026-920100 days apartPrivilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
    35Monitor
  • CVE-2026-920430 days apartPrivilege escalation due to incorrect boundary conditions in the Audio/Video 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).

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

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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.

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

Vulnerable

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

Fixed

c
char buf[256];if (pkt->len > sizeof(buf)) {  return -EINVAL;}memcpy(buf, pkt->data, pkt->len);

Noroxi analysis

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Change log

  1. Fix✗ → ✓

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References

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