CVE-2025-10531 | Mitigation bypass in the Web Compatibility: Tooling component

Mitigation bypass in the Web Compatibility: Tooling component. This vulnerability was fixed in Firefox 143 and Thunderbird 143.

Published: 2025-09-16 Last update: 2026-04-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-10531 is rated Low Risk (23.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2025-10531

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 2026-02-12 0.05% 0.03% -0.03%
2 2026-01-16 0.02% 0.05% +0.03%
3 2025-09-17 — 0.02% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-10531

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N 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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.5 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2025-10531

OS Trackers for CVE-2025-10531

vendor priority summary link
alpine — CVE-2025-10531: 2 source package rows (firefox, thunderbird); 232 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 232. https://security.alpinelinux.org/vuln/CVE-2025-10531
debian not yet assigned CVE-2025-10531 not yet assigned priority: Debian including 1 source packages (firefox), 1 status rows across 1 suites (sid): resolved 1. https://security-tracker.debian.org/tracker/CVE-2025-10531
redhat medium — https://access.redhat.com/security/cve/CVE-2025-10531
ubuntu medium CVE-2025-10531 medium priority: Ubuntu including 2 source packages (firefox, thunderbird), 10 status rows across 5 suites (jammy, noble, plucky, questing, upstream): not-affected 8, needs-triage 2. https://ubuntu.com/security/CVE-2025-10531

Affected software / configurations for CVE-2025-10531

Vendor Product Version Raw CPE
mozilla firefox < 143.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
mozilla thunderbird < 143.0 cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

References for CVE-2025-10531

cvelogic Threat Intelligence