Security readout for executives and security teams
Plain-English summary
A malicious website could mislead a user into making that site the default handler for a custom URL protocol. This is a user-interaction issue with limited confidentiality impact, not a remote takeover finding. Mozilla reports fixes in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
Executive priority
Treat as a routine browser and email-client patching item. It has real phishing-style risk but limited impact and no cited active exploitation. Prioritize normal endpoint update cycles, with faster action for shared, high-risk, or poorly managed user environments.
Technical view
CVE-2025-1935 is a clickjacking issue affecting Mozilla protocol-handler registration UI. A page could trick a user into approving registerProtocolHandler behavior for a custom protocol. CVSS 3.1 is 4.3, with network attack vector, low complexity, no privileges, required user interaction, and low confidentiality impact.
Likely exposure
Exposure is most relevant where Firefox, Firefox ESR, Thunderbird, or Thunderbird ESR are below the Mozilla fixed releases. Organizations with managed browsers, email clients, kiosk systems, or shared workstations should verify deployed versions and protocol-handler settings.
Exploitation context
The source bundle does not cite CISA KEV listing or active exploitation. Abuse requires user interaction with a deceptive web page and successful UI tricking. The main concern is unwanted protocol-handler registration, which could later route custom links through an attacker-controlled site.
Researcher notes
Evidence supports clickjacking against protocol-handler registration UI, not code execution or credential theft. The CVE metadata maps to CWE-79 and CVSS confidentiality-low only. Public sources provided do not include proof-of-concept details, exploitation telemetry, or compensating configuration guidance beyond updating.
Mitigation direction
- Update Firefox to version 136 or later where applicable.
- Update Firefox ESR to version 128.8 or later.
- Update Thunderbird to version 136 or later where applicable.
- Update Thunderbird ESR to version 128.8 or later.
- For Debian LTS systems, follow the referenced Debian security advisory.
Validation and detection
- Inventory Firefox and Thunderbird versions across managed endpoints.
- Confirm deployed versions meet or exceed Mozilla fixed releases.
- Review browser and mail-client update compliance reporting.
- Check for unexpected custom protocol-handler registrations where operationally feasible.
- Track Mozilla and OS vendor advisories for any follow-up guidance.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2025-1935 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N2.81.4CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=1866661CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-14/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-16/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-17/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-18/CVE reference, mozilla
- https://lists.debian.org/debian-lts-announce/2025/03/msg00006.htmlCVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.