CVE-2023-4056

Memory safety bugs present in Firefox 115, Firefox ESR 115.0, Firefox ESR 102.13, Thunderbird 115.0, and Thunderbird 102.13. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.

Published: 2023-08-01 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-4056 is rated Moderate Risk (57.9/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.85%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-4056

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-18 0.86% 0.85% -0.01%
2 2026-06-15 0.60% 0.86% +0.25%
3 2026-04-19 — 0.60% —

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-4056

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]

Weakness enumeration for CVE-2023-4056

OS Trackers for CVE-2023-4056

vendor priority summary link
alpine critical CVE-2023-4056: 2 source package rows (firefox, firefox-esr); 80 state rows across 6 repos (3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 6, open 74. https://security.alpinelinux.org/vuln/CVE-2023-4056
debian not yet assigned CVE-2023-4056 not yet assigned priority: Debian including 3 source packages (firefox, firefox-esr, thunderbird), 11 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 11. https://security-tracker.debian.org/tracker/CVE-2023-4056
gentoo high CVE-2023-4056: 1 GLSA(s) (202402-25), 2 atom(s) (mail-client/thunderbird, mail-client/thunderbird-bin); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-4056
redhat high — https://access.redhat.com/security/cve/CVE-2023-4056
ubuntu medium CVE-2023-4056 medium priority: Ubuntu including 8 source packages (firefox, mozjs102, …), 72 status rows across 9 suites (bionic, focal, jammy, lunar, mantic, noble, trusty, upstream, xenial): DNE 38, ignored 23, released 7, not-affected 4. https://ubuntu.com/security/CVE-2023-4056

Affected software / configurations for CVE-2023-4056

Vendor Product Version Raw CPE
mozilla firefox < 116.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
mozilla firefox >= 102.0, < 102.14 cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
mozilla firefox >= 115.0, < 115.1 cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
debian debian_linux 12.0 cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*

References for CVE-2023-4056

cvelogic Threat Intelligence