CVE-2024-5692VulnerabilityPublished 11 Jun 2024Updated 27 Feb 2026

CVE-2024-5692: Mozilla Firefox · Bypass of file name restrictions during saving

Affects Mozilla FirefoxSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 127 or 115.12 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 127, 115.12

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Jun 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Mozilla Firefox to 127 or 115.12.

Affected software

Product	Affected	Fixed in
Mozilla Firefox	Affected <127 <115.12	Fixed in 127 115.12

AI-suggested

To mitigate this vulnerability, organizations and users should promptly update Mozilla Firefox to version 127 or later and Thunderbird to version 115.12 or later, where the issue has been addressed. If you cannot patch yet, users should exercise caution when saving files from untrusted or unknown sources, especially when the 'Save As' dialog is triggered. Security teams should consider deploying endpoint protection solutions that can detect and block suspicious file types or extensions, particularly those that might be saved through this bypass. Implementing strict application whitelisting and restricting execution of files with uncommon or potentially dangerous extensions can reduce the impact of any malicious files saved via this vulnerability. User education on the risks of saving files from untrusted websites and recognizing phishing attempts is also important. Monitoring for unusual file creation events with disallowed extensions on Windows endpoints can help detect exploitation attempts. Finally, organizations should maintain up-to-date inventories of affected software versions to ensure timely patch management.

Description

On Windows 10, when using the 'Save As' functionality, an attacker could have tricked the browser into saving the file with a disallowed extension such as `.url` by including an invalid character in the extension. *Note:* This issue only affected Windows operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

Impact

The primary impact of this vulnerability is the potential for attackers to bypass file extension restrictions during file saving, which can lead to several security risks. By saving files with disallowed extensions such as '.url' or other potentially dangerous types, attackers can facilitate phishing attacks, social engineering, or delivery of malicious payloads that might be executed by the user or the system. This undermines the browser's security controls designed to prevent inadvertent saving of harmful files. While the vulnerability does not directly compromise confidentiality or availability, it threatens the integrity of the user's system by enabling the introduction of malicious files. Organizations relying on Firefox or Thunderbird on Windows 10 could see increased risk of targeted attacks leveraging this flaw, especially in environments where users frequently download or save files from untrusted sources. The requirement for user interaction limits automated exploitation but does not eliminate risk, particularly in spear-phishing or drive-by download scenarios. Since the vulnerability is Windows-specific, organizations with a large Windows user base are more exposed. The absence of known exploits in the wild reduces immediate risk but patching is critical to prevent future exploitation.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Feb 2026, 22:27 UTC

Technical details

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