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NVD / CVE Program· CNA mozilla

CVE-2023-6204: On some systems—depending on the graphics settings and drivers—it was possible to force an out-of-bounds read and leak memory data into the…

Noroxi assessment

Priority: Monitor (action score 26/100)

  • 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: 0.84% (FIRST EPSS); higher than 58.1% of all records.
  • 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:8) 115.5.0-1.el8_9.alma.1; thunderbird (AlmaLinux:8) 115.5.0-1.el8_9.alma.1; firefox (AlmaLinux:9) 115.5.0-1.el9_3.alma.1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to firefox (AlmaLinux:8) 115.5.0-1.el8_9.alma.1; thunderbird (AlmaLinux:8) 115.5.0-1.el8_9.alma.1; firefox (AlmaLinux:9) 115.5.0-1.el9_3.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

On some systems—depending on the graphics settings and drivers—it was possible to force an out-of-bounds read and leak memory data into the images created on the canvas element. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Nov 21, 2023
Updated
Jun 17, 2026
EPSS
0.8% · 58th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

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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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  • when exploit code appears or is weaponized
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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
mozillafirefox esr
mozillathunderbird
debiandebian linux

Affected versions

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

  • debian debian linux10.0
  • debian debian linux11.0
  • debian debian linux12.0
  • mozilla firefoxbefore 120.0
  • mozilla firefox esrbefore 115.5.0
  • mozilla thunderbirdbefore 115.5

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

    • unspecified and later · before 120affected

  • Mozilla Firefox ESR

    • unspecified and later · before 115.5.0affected

  • Mozilla Thunderbird

    • unspecified and later · before 115.5affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8firefoxbefore 115.5.0-1.el8_9.alma.1115.5.0-1.el8_9.alma.1
AlmaLinux:8thunderbirdbefore 115.5.0-1.el8_9.alma.1115.5.0-1.el8_9.alma.1
AlmaLinux:9firefoxbefore 115.5.0-1.el9_3.alma.1115.5.0-1.el9_3.alma.1
AlmaLinux:9firefox-x11before 115.5.0-1.el9_3.alma.1115.5.0-1.el9_3.alma.1
AlmaLinux:9thunderbirdbefore 115.5.0-1.el9_3.alma115.5.0-1.el9_3.alma
Alpine:v3.18firefox-esrbefore 115.5.0-r0115.5.0-r0
Alpine:v3.18thunderbirdbefore 115.5.0-r0115.5.0-r0
Debian:10firefox-esrbefore 115.5.0esr-1~deb10u1115.5.0esr-1~deb10u1
Debian:10thunderbirdbefore 1:115.5.0-1~deb10u11:115.5.0-1~deb10u1
Debian:11firefox-esrbefore 115.5.0esr-1~deb11u1115.5.0esr-1~deb11u1
Debian:11thunderbirdbefore 1:115.5.0-1~deb11u11:115.5.0-1~deb11u1
Debian:12firefox-esrbefore 115.5.0esr-1~deb12u1115.5.0esr-1~deb12u1
Debian:12thunderbirdbefore 1:115.5.0-1~deb12u11:115.5.0-1~deb12u1
Debian:13firefox-esrbefore 115.5.0esr-1115.5.0esr-1
Debian:13thunderbirdbefore 1:115.5.0-11:115.5.0-1
openSUSE:Leap 15.4MozillaFirefoxbefore 115.6.0-150200.152.120.1115.6.0-150200.152.120.1
openSUSE:Leap 15.4MozillaThunderbirdbefore 115.5.0-150200.8.139.1115.5.0-150200.8.139.1
openSUSE:TumbleweedMozillaFirefoxbefore 120.0-1.1120.0-1.1
openSUSE:TumbleweedMozillaThunderbirdbefore 115.5.0-1.1115.5.0-1.1
Red Hat:enterprise_linux:7::clientfirefoxbefore 0:115.5.0-1.el7_90:115.5.0-1.el7_9
Red Hat:enterprise_linux:7::clientfirefox-debuginfobefore 0:115.5.0-1.el7_90:115.5.0-1.el7_9
Red Hat:enterprise_linux:7::clientthunderbirdbefore 0:115.5.0-1.el7_90:115.5.0-1.el7_9
Red Hat:enterprise_linux:7::clientthunderbird-debuginfobefore 0:115.5.0-1.el7_90:115.5.0-1.el7_9
Red Hat:enterprise_linux:8::appstreamfirefoxbefore 0:115.5.0-1.el8_90:115.5.0-1.el8_9

+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…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-2023-5731Oct 25, 2023 · Memory safety bugs present in Firefox 118.
    39Monitor
  • ← EarlierCVE-2023-5732Oct 25, 2023 · Address bar spoofing via bidirectional characters
    26Monitor
  • Later →CVE-2023-6205Nov 21, 2023 · It was possible to cause the use of a MessagePort after it had already been freed, which could potentially have led to an exploitable crash.
    26Monitor

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:firefox115.5.0-1.el9_3.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:firefox-x11115.5.0-1.el9_3.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:thunderbird115.5.0-1.el8_9.alma.1 · AlmaLinux:8Package registry (OSV)
alpine:firefox-esr115.5.0-r0 · Alpine:v3.18Package registry (OSV)
alpine:thunderbird115.5.0-r0 · Alpine:v3.18Package registry (OSV)
debian:firefox-esr115.5.0esr-1~deb12u1 · Debian:12Package registry (OSV)
debian:thunderbird1:115.5.0-1~deb12u1 · Debian:12Package registry (OSV)
opensuse:MozillaFirefox115.6.0-150200.152.120.1 · openSUSE:Leap 15.4Package registry (OSV)
opensuse:MozillaThunderbird115.5.0-150200.8.139.1 · openSUSE:Leap 15.4Package registry (OSV)
red hat:firefox0:115.5.0-1.el9_3 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:firefox-debuginfo0:115.5.0-1.el9_3 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:firefox-debugsource0:115.5.0-1.el9_3 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:firefox-x110:115.5.0-1.el9_3 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:thunderbird0:115.5.0-1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:thunderbird-debuginfo0:115.5.0-1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:thunderbird-debugsource0:115.5.0-1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
rocky linux:thunderbird0:115.5.0-1.el8_9 · Rocky Linux:8Package registry (OSV)
suse:MozillaFirefox115.6.0-112.194.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5Package registry (OSV)
suse:MozillaFirefox115.6.0-150200.152.120.1 · SUSE:Linux Enterprise Module for Desktop Applications 15 SP4Package registry (OSV)
suse:MozillaThunderbird115.5.0-150200.8.139.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP4Package 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-2024-29943122 days apartAn attacker was able to perform an out-of-bounds read or write on a JavaScript object by fooling range-based bounds check elimination.
    46Plan
  • CVE-2022-31747334 days apartMozilla developers Andrew McCreight, Nicolas B.
    39Monitor
  • CVE-2024-3854147 days apartIn some code patterns the JIT incorrectly optimized switch statements and generated code with out-of-bounds-reads.
    35Monitor
  • CVE-2024-7522259 days apartEditor code failed to check an attribute value.
    35Monitor
  • CVE-2022-46872334 days apartAn attacker who compromised a content process could have partially escaped the sandbox to read arbitrary files via clipboard-related IPC…
    34Monitor
  • CVE-2024-6606231 days apartOut-of-bounds read in clipboard component
    32Monitor

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.

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

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records