Cyber Resilience

CVE-2026-2807

Memory Safety in Mozilla Firefox ≤ 148.0

Published
24 February 2026
Modified
15 July 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0024 16th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-2807 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 16th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-2807 encompasses multiple memory safety bugs in Firefox 147 and Thunderbird 147, classified under CWE-787 (Out-of-bounds Write). These bugs demonstrated evidence of memory corruption, and Mozilla presumes that with sufficient effort, some could be exploited to execute arbitrary code. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical.

Remote attackers can exploit this vulnerability over the network with low attack complexity, without requiring user privileges or interaction. Successful exploitation would grant high-impact confidentiality, integrity, and availability consequences, potentially enabling arbitrary code execution on affected systems.

Mozilla addressed CVE-2026-2807 in Firefox 148 and Thunderbird 148. Detailed information is available in Mozilla Security Advisories MFSA2026-13 and MFSA2026-16, along with the associated Bugzilla bugs (1756056, 1999402, 2004872, 2006037, 2012855).

EU & UK References

Vulnerability Data

Memory safety bugs present in Firefox 147 and Thunderbird 147. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was…

more

fixed in Firefox 148 and Thunderbird 148.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-3034Same product: Mozilla Firefox
CVE-2025-5269Same product: Mozilla Firefox
CVE-2024-6615Same product: Mozilla Firefox
CVE-2025-0247Same product: Mozilla Firefox
CVE-2025-1020Same product: Mozilla Firefox
CVE-2025-1938Same product: Mozilla Firefox
CVE-2025-1016Same product: Mozilla Firefox
CVE-2025-0242Same product: Mozilla Firefox
CVE-2025-5272Same product: Mozilla Firefox
CVE-2025-1017Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 148.0
mozilla
thunderbird
≤ 148.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation (including fuzzing and bounds checks) finds out-of-bounds write flaws before deployment.

Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.

Input validation can structurally reject or sanitize data that would otherwise trigger an out-of-bounds write.

Memory-protection mechanisms limit the exploitability and blast radius of a successful out-of-bounds write.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

prevents

Application security requirements can specify bounds-checking and safe memory handling.

prevents

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References