It was possible to interrupt the processing of a RegExp bailout and run additional JavaScript, potentially triggering garbage collection when the engine was not expecting it. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
Conclusion & alert: CVE-2025-1934 is rated Low Risk (38.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.43%). 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 | 2026-06-15 | 0.32% | 0.43% | +0.11% |
| 2 | 2026-03-02 | 0.46% | 0.32% | -0.14% |
| 3 | 2025-12-19 | — | 0.46% | — |
Full EPSS history (11 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
2.8 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2025-1934: 3 source package rows (firefox, firefox-esr, thunderbird); 342 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 342. | https://security.alpinelinux.org/vuln/CVE-2025-1934 |
debian
|
not yet assigned | CVE-2025-1934 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-2025-1934 |
gentoo
|
high | CVE-2025-1934: 3 GLSA(s) (202505-02, 202505-03, 202505-08), 5 atom(s) (dev-lang/spidermonkey, mail-client/thunderbird, mail-client/thunderbird-bin, www-client/firefox, www-client/firefox-bin); latest impact high. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2025-1934 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2025-1934 |
suse
|
high | CVE-2025-1934 severity important: SUSE including 35 source package names (MozillaFirefox-128.8.0-112.249.3, MozillaFirefox-128.8.0-150200.152.173.1, …), 137 product×package rows across 48 product lines (Container suse/kiosk/firefox-esr, Image SLES12-SP5-SAP-Azure-LI-BYOS-Production, … (48 product lines)): Fixed 137. | https://www.suse.com/security/cve/CVE-2025-1934/ |
ubuntu
|
medium | CVE-2025-1934 medium priority: Ubuntu including 9 source packages (firefox, mozjs102, …), 65 status rows across 8 suites (bionic, focal, jammy, noble, oracular, plucky, questing, upstream): DNE 34, ignored 10, needs-triage 9, not-affected 9, released 3. | https://ubuntu.com/security/CVE-2025-1934 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mozilla | firefox | < 128.8.0 | cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* |
| mozilla | firefox | < 136.0 | cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* |
| mozilla | thunderbird | < 128.8.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |
| mozilla | thunderbird | >= 129.0, < 136.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1942881 | Issue Tracking Permissions Required |
| https://www.mozilla.org/security/advisories/mfsa2025-14/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-16/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-17/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-18/ | Vendor Advisory |
| https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html |