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CVE-2023-6859

24
FAUCET Score

CVE-2023-6859 is a high-severity use-after-free vulnerability affecting Mozilla Firefox, Firefox ESR, and Thunderbird versions prior to 121 and 115.6 respectively. This flaw occurs during TLS socket creation under memory pressure, potentially leading to arbitrary code execution or denial of service. With a CVSS score of 8.8, it is easily exploitable over the network with user interaction, allowing for high impact on confidentiality, integrity, and availability. Despite its severity, there is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

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:*:*:*:*:*:*:*:*
< 115.6CPE matchmatch criteria
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.09%
Probability of exploitation in next 30 days
EPSS Percentile
62.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0109 is in the 61st percentile among its peer group of 14,875 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (27)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.2 Extended Update SupportFixed in: thunderbird-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 7Fixed in: thunderbird-0:115.6.0-1.el7_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: thunderbird-0:115.6.0-1.el8_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 Advanced Update SupportFixed in: thunderbird-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 Telecommunications Update ServiceFixed in: thunderbird-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 8.2 Update Services for SAP SolutionsFixed in: thunderbird-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 Advanced Mission Critical Update SupportFixed in: thunderbird-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 Telecommunications Update ServiceFixed in: thunderbird-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 8.4 Update Services for SAP SolutionsFixed in: thunderbird-0:115.6.0-1.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Extended Update SupportFixed in: thunderbird-0:115.6.0-1.el8_6
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: thunderbird-0:115.6.0-1.el8_8
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: thunderbird-0:115.6.0-1.el9_3
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: thunderbird-0:115.6.0-1.el9_0
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
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
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2023-6859Moderate

Mozilla: Use-after-free in PR_GetIdentitiesLayer

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
lists.debian.org / debian-lts-announce/2023/12/msg00021.html
Mailing ListThird Party Advisory
security.gentoo.org / glsa/202401-10
Third Party Advisory
debian.org / security/2023/dsa-5581
Third Party Advisory
debian.org / security/2023/dsa-5582
Third Party Advisory
mozilla.org / security/advisories/mfsa2023-54
Vendor Advisory
mozilla.org / security/advisories/mfsa2023-55
Vendor Advisory
mozilla.org / security/advisories/mfsa2023-56
Vendor Advisory