Information disclosure in the Networking component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
Conclusion & alert: CVE-2026-0883 is rated Low Risk (23.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Mandatory action: 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.
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 | 2026-01-14 | — | 0.03% | — |
Full EPSS history (1 record total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.3 | 3.1 | MEDIUM |
|
3.9 | 1.4 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2026-0883: 3 source package rows (firefox, firefox-esr, thunderbird); 274 state rows across 2 repos (3.23-community, edge-community); fixed 0, open 274. | https://security.alpinelinux.org/vuln/CVE-2026-0883 |
debian
|
not yet assigned | CVE-2026-0883 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-2026-0883 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2026-0883 |
suse
|
high | CVE-2026-0883 severity important: SUSE including 47 source package names (2.2.0-4.49:libopenssl3-3.1.4-slfo.1.1_5.1, 2.2.0-4.50:libopenssl3-3.1.4-slfo.1.1_5.1, …), 215 product×package rows across 87 product lines (Container suse/sl-micro/6.0/baremetal-os-container, Container suse/sl-micro/6.0/base-os-container, … (87 product lines)): Fixed 211, First Fixed 4. | https://www.suse.com/security/cve/CVE-2026-0883/ |
ubuntu
|
medium | CVE-2026-0883 medium priority: Ubuntu including 9 source packages (firefox, mozjs102, …), 58 status rows across 8 suites (bionic, focal, jammy, noble, plucky, questing, resolute, upstream): DNE 29, needs-triage 10, ignored 9, not-affected 9, released 1. | https://ubuntu.com/security/CVE-2026-0883 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mozilla | firefox | < 140.7.0 | cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* |
| mozilla | firefox | < 147.0 | cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* |
| mozilla | thunderbird | < 140.7.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:* |
| mozilla | thunderbird | < 147.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:* |
| URL | Tags |
|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1989340 | Permissions Required |
| https://www.mozilla.org/security/advisories/mfsa2026-01/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2026-03/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2026-04/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2026-05/ | Vendor Advisory |