VulnerabilityPublished 26 Nov 2024Updated 3 Nov 2025

CVE-2024-11696: Mozilla Firefox · Unhandled Exception in Add-on Signature Verification

Affects Mozilla FirefoxSource CVE Database V5

Not known to be exploited · CVSS 5.4 Medium : upgrade to 133 or 128.5 when convenient.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

5.4Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 133, 128.5

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 26 Nov 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 26 Oct 2026.

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 or the CVSS exploit maturity 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 133 or 128.5.

Affected software

Product	Affected	Fixed in
Mozilla Firefox	Affected <133 <128.5	Fixed in 133 128.5

AI-suggested

European organizations should prioritize updating Firefox and Thunderbird to versions 133 and 128.5 ESR or later, respectively, as soon as these patches become available. If you cannot patch yet, organizations should audit installed extensions for any that have invalid or unsupported manifests and consider disabling or removing suspicious add-ons. Implementing application control policies to restrict installation of unapproved extensions can reduce risk. User awareness training should emphasize caution when installing or interacting with browser extensions, especially from untrusted sources. Monitoring browser logs for signature verification errors may help detect exploitation attempts. Organizations may also consider deploying endpoint detection and response (EDR) tools capable of identifying anomalous extension behavior. For environments with high security requirements, temporarily restricting extension installation or using browser configurations that enforce stricter extension policies can provide additional protection. Coordination with Mozilla's security advisories and timely application of official patches remain critical.

Description

The application failed to account for exceptions thrown by the `loadManifestFromFile` method during add-on signature verification. This flaw, triggered by an invalid or unsupported extension manifest, could have caused runtime errors that disrupted the signature validation process. As a result, the enforcement of signature validation for unrelated add-ons may have been bypassed. Signature validation in this context is used to ensure that third-party applications on the user's computer have not tampered with the user's extensions, limiting the impact of this issue. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

Impact

For European organizations, this vulnerability poses a risk to the integrity and confidentiality of browser extensions used within their environments. Organizations that rely heavily on Firefox or Thunderbird for communication and web access, especially those enforcing strict extension policies, may face increased risk of malicious or tampered extensions being loaded undetected. This could lead to data leakage, credential theft, or unauthorized access if malicious extensions exploit this bypass. The disruption of signature validation undermines trust in the extension ecosystem, potentially allowing attackers to escalate privileges or persist within user environments. While availability is not directly impacted, the indirect consequences of compromised extensions could affect operational security and user privacy. Sectors such as finance, government, and critical infrastructure in Europe, which often mandate strict software integrity controls, may be particularly sensitive to this vulnerability. The requirement for user interaction to exploit limits automated mass exploitation but does not eliminate targeted attacks. The absence of known exploits in the wild reduces immediate risk but should not lead to complacency given the potential impact.

CWE-347Improper Verification of Cryptographic Signature (opens in a new tab)
Base weaknessOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
Padding Oracle Crypto Attack (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Nov 2025, 23:18 UTC

WeaknessesCWE-347

Technical details

References

Community reviews

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