Firefox Storage Cache API Side-Channel Info Disclosure (fixed 154)
CVE-2026-74954 Published on August 18, 2026
Information disclosure due to side-channel in the Storage: Cache API component
Information disclosure due to side-channel in the Storage: Cache API component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
Vulnerability Analysis
CVE-2026-74954 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Type
What is a Side Channel Attack Vulnerability?
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not. Discrepancies can take many forms, and variations may be detectable in timing, control flow, communications such as replies or requests, or general behavior. These discrepancies can reveal information about the product's operation or internal state to an unauthorized actor. In some cases, discrepancies can be used by attackers to form a side channel.
CVE-2026-74954 has been classified to as a Side Channel Attack vulnerability or weakness.
Products Associated with CVE-2026-74954
stack.watch emails you whenever new vulnerabilities are published in Mozilla Firefox or Mozilla Thunderbird. Just hit a watch button to start following.
Affected Versions
Mozilla Firefox:- Version 153.1, <= 153.* is unaffected.
- Version 154, <= * is unaffected.
- Version 153.1, <= 153.* is unaffected.
- Version 154, <= * is unaffected.