CVE-2026-12297
CRITICAL 9.6Sandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
Severe if exploited (CVSS 9.6), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 32nd percentile
Impact if exploited
9.6CVSS 3.1 · CRITICAL
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ⚠User interaction: A user must take an action (click / open a file)
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-12297/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-12297/poc.json
Affected
Products Firefox Thunderbird Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 10.0 Extended Update Support Red Hat Enterprise Linux 7 Extended Lifecycle Support Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.4 Extended Update Support Long Life Add On Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.6 Extended Update Support Long Life Add On Red Hat Enterprise Linux 8.8 Telecommunications Update Service Red Hat Enterprise Linux 8.8 Update Services For Sap Solutions
Weakness (CWE)
- CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
- CWE-653: Improper Isolation or Compartmentalization
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Mozilla | Firefox | < 115.37.0 |
| Mozilla | Firefox | < 152.0.0 |
| Mozilla | Firefox | ≥ 128.0 and < 140.12.0 |
| Mozilla | Thunderbird | < 140.12.0 |
| Mozilla | Thunderbird | < 152.0.0 |
All CVSS metrics
- CRITICAL 9.6 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H - HIGH 7.5 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H - CRITICAL 9.6 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H - HIGH 7.5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
References
Advisories
- https://www.mozilla.org/security/advisories/mfsa2026-57/
- https://www.mozilla.org/security/advisories/mfsa2026-58/
- https://www.mozilla.org/security/advisories/mfsa2026-59/
- https://www.mozilla.org/security/advisories/mfsa2026-60/
- https://www.mozilla.org/security/advisories/mfsa2026-61/
- https://access.redhat.com/errata/RHSA-2026:38506
- https://access.redhat.com/errata/RHSA-2026:36100
- https://access.redhat.com/errata/RHSA-2026:38751
- https://access.redhat.com/errata/RHSA-2026:27733
- https://access.redhat.com/errata/RHSA-2026:30846
- https://access.redhat.com/errata/RHSA-2026:27717
- https://access.redhat.com/errata/RHSA-2026:33445
- https://access.redhat.com/errata/RHSA-2026:36102
- https://access.redhat.com/errata/RHSA-2026:39428
- https://access.redhat.com/errata/RHSA-2026:37210
- https://access.redhat.com/errata/RHSA-2026:39141
- https://access.redhat.com/errata/RHSA-2026:36103
- https://access.redhat.com/errata/RHSA-2026:39142
- https://access.redhat.com/errata/RHSA-2026:36101
- https://access.redhat.com/errata/RHSA-2026:39706
- https://access.redhat.com/errata/RHSA-2026:39011
- https://access.redhat.com/errata/RHSA-2026:38753
- https://access.redhat.com/errata/RHSA-2026:37391
- https://access.redhat.com/errata/RHSA-2026:38750
- https://access.redhat.com/errata/RHSA-2026:27734
- https://access.redhat.com/errata/RHSA-2026:29940