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CVE-2023-6865

20
FAUCET Score

CVE-2023-6865 describes a vulnerability in Firefox ESR < 115.6 and Firefox < 121, where the EncryptingOutputStream could expose uninitialized data. This medium-severity vulnerability (CVSS 6.5) requires user interaction and network access, potentially leading to high confidentiality impact by writing sensitive data to local disk, particularly relevant in private browsing mode. While a SecurityWeek article incorrectly mentioned Remote Code Execution, the official description indicates a local data exposure issue. There is no known active exploitation, public exploit code, or significant community discussion, and it is not listed in the KEV catalog.

Impacted Technologies

VendorProductVersion(s)CPE
< 121.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
< 115.6CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
11.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
12.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.89%
Probability of exploitation in next 30 days
EPSS Percentile
55.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0089 is in the 66th percentile among its peer group of 26,236 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (14)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.2 Extended Update SupportFixed in: firefox-0:115.6.0-1.el9_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:115.6.0-1.el7_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: firefox-0:115.6.0-1.el8_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Advanced Update SupportFixed in: firefox-0:115.6.0-1.el8_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Telecommunications Update ServiceFixed in: firefox-0:115.6.0-1.el8_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Update Services for SAP SolutionsFixed in: firefox-0:115.6.0-1.el8_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportFixed in: firefox-0:115.6.0-1.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Telecommunications Update ServiceFixed in: firefox-0:115.6.0-1.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Update Services for SAP SolutionsFixed in: firefox-0:115.6.0-1.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Extended Update SupportFixed in: firefox-0:115.6.0-1.el8_6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.8 Extended Update SupportFixed in: firefox-0:115.6.0-1.el8_8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: firefox-0:115.6.0-1.el9_3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.0 Extended Update SupportFixed in: firefox-0:115.6.0-1.el9_0
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2023-6865Important

Mozilla: Potential exposure of uninitialized data in <code>EncryptingOutputStream</code>

Dec 19, 2023

References

bugzilla.mozilla.org / show_bug.cgi
Issue TrackingPermissions Required
lists.debian.org / debian-lts-announce/2023/12/msg00020.html
Mailing ListThird Party Advisory
security.gentoo.org / glsa/202401-10
Third Party Advisory
debian.org / security/2023/dsa-5581
Third Party Advisory
mozilla.org / security/advisories/mfsa2023-54
Vendor Advisory
mozilla.org / security/advisories/mfsa2023-56
Vendor Advisory