CVE-2026-124859: Sandbox escape due to incorrect boundary conditions in the Storage: Cache API component
Source GCVE Database
Not known to be exploited · CVSS 9.6 Critical · fixed in 160 : patch Firefox as a priority.
Data as of 10 Nov 2026, 18:03 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 9.6 |
|---|
- Patch
- Available – fixed in 160, 153.7, 115.45
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.
What to do
Upgrade the Ubuntu to 160 (ubuntu/firefox package); 153.7 or 115.45 (ubuntu/firefox-esr package).
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntuubuntu/firefoxpkg:deb/ubuntu/firefoxOther threats | Affected
| Fixed in
|
Ubuntuubuntu/firefox-esrpkg:deb/ubuntu/firefox-esrOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users and administrators should update Firefox to version 160 or later, or Firefox ESR to version 115.45 or later, where this vulnerability has been fixed. Applying these official fixes fully mitigates the risk.
Description
CVE-2026-124859 is a critical sandbox escape vulnerability in the Storage: Cache API component of Firefox. It arises from incorrect boundary conditions that allow an attacker to break out of the sandbox environment. This flaw was fixed in Firefox 160 and Firefox ESR versions 115.45 and 153.7. The vulnerability has a high CVSS score of 9.6, indicating severe impact on confidentiality, integrity, and availability. No known exploits in the wild have been reported at this time.
References
- nvd.nist.gov/vuln/detail/CVE-2026-124859 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2074179 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-125 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-126 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-127 (opens in a new tab)