Security readout for executives and security teams
Plain-English summary
CVE-2026-0885 is a Mozilla memory-safety flaw in JavaScript garbage collection. Mozilla says it is fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7. Public sources provided do not indicate active exploitation. Treat it as a routine but timely browser and mail-client update priority.
Executive priority
Medium priority. This affects widely deployed end-user software and should be remediated through standard patch processes. Escalate if your environment has delayed browser or Thunderbird updates, but current sources do not support emergency treatment based on active exploitation.
Technical view
The issue is a use-after-free vulnerability in the JavaScript: GC component, classified as CWE-416. The supplied CVSS 3.1 score is 6.5, with network attack vector, low complexity, no privileges required, and low confidentiality and availability impact. Integrity impact is listed as none.
Likely exposure
Organizations using Mozilla Firefox, Firefox ESR, or Thunderbird below the fixed releases may be exposed. The provided data does not identify specific operating systems, configurations, or vulnerable version ranges beyond the fixed versions named by Mozilla.
Exploitation context
The source bundle marks CISA KEV status as false, and no cited source reports active exploitation. The CVSS vector indicates remote network reachability with no privileges required, but the sources do not describe a working exploit or real-world attacks.
Researcher notes
Evidence is limited to the CVE description, Mozilla advisories, and Bugzilla reference. The Bugzilla entry may restrict details. Do not infer code execution or exploitability beyond the CVSS impacts and CWE-416 classification unless Mozilla publishes additional technical detail.
Mitigation direction
- Update Firefox to version 147 or later, where applicable.
- Update Firefox ESR to 140.7 or later, where applicable.
- Update Thunderbird to version 147 or 140.7 or later, where applicable.
- Check Mozilla advisories for platform-specific update guidance.
- Prioritize managed browser and mail-client update compliance.
Validation and detection
- Inventory deployed Firefox, Firefox ESR, and Thunderbird versions.
- Confirm endpoints are at or above Mozilla’s fixed versions.
- Review update-management reports for failed or deferred updates.
- Monitor Mozilla advisories for any revised affected-version details.
- Check vulnerability scanner results against CVE-2026-0885.
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-416: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2026-0885 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
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
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.
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:N/S:U/C:L/I:N/A:L3.92.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=2003607CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-01/CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-03/CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-04/CVE reference
- https://www.mozilla.org/security/advisories/mfsa2026-05/CVE reference
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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.