CVE-2026-100773

Analyzed Analyzed - Analysis Complete

Use-after-free in Firefox Storage IndexedDB

Publication date: 2026-09-29

Last updated on: 2026-10-06

Assigner: Mozilla Corporation

Description

Use-after-free in the Storage: IndexedDB component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-29

Last Modified

2026-10-06

Generated

2026-10-19

AI Q&A

2026-09-29

EPSS Evaluated

2026-10-18

NVD

CVE-2026-100773

EUVD

EUVD-2026-88925

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	From 154.0.0 (inc) to 157.0.0 (exc)
mozilla	thunderbird	From 154.0 (inc) to 157.0 (exc)
mozilla	thunderbird	From 140.0 (inc) to 140.17.0 (exc)
mozilla	thunderbird	From 153.0 (inc) to 153.4.0 (exc)
mozilla	firefox	From 140.0.0 (inc) to 140.17.0 (exc)
mozilla	firefox	From 153.0.0 (inc) to 153.4.0 (exc)
mozilla	firefox	From 115.0 (inc) to 115.42.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This is a use-after-free vulnerability in Firefox's Storage: IndexedDB component. Use-after-free occurs when a program continues to use memory after it has been freed, potentially leading to crashes or arbitrary code execution. The issue was addressed in specific Firefox versions including ESR 153.4, Firefox 157, ESR 115.42, and ESR 140.17.

Detection Guidance

Detecting this vulnerability requires checking Firefox version against patched releases. Compare your installed version with Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, or Firefox ESR 140.17. Use commands like 'firefox --version' or check 'about:support' in Firefox.

Impact Analysis

This vulnerability could allow an attacker to execute arbitrary code on your system by exploiting the use-after-free flaw in Firefox's IndexedDB storage. This might lead to system crashes, data corruption, or unauthorized access to sensitive information if the attacker gains control of your browser session.

Compliance Impact

This vulnerability could potentially lead to unauthorized access or manipulation of sensitive data stored in IndexedDB, which may impact compliance with GDPR (data confidentiality) and HIPAA (protected health information integrity). The high CVSS score indicates significant impact on confidentiality, integrity, and availability of data.

Mitigation Strategies

Update Firefox to the latest patched version immediately. If using ESR, upgrade to Firefox ESR 153.4, 115.42, or 140.17. Disable IndexedDB if not required or restrict access to untrusted websites.

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