VulnerabilityPublished 30 Apr 2024Updated 2 Aug 2024

CVE-2024-29384: CSS-Exfil-Protection · Information Exposure

Affects CSS-Exfil-ProtectionSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
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: None: The vulnerable system can be exploited without any interaction from any user.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within 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 30 Apr 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

Affected software

Product	Affected	Fixed in
GitHubmlgualtieri/CSS-Exfil-Protection`pkg:github/mlgualtieri/CSS-Exfil-Protection`Other threats	Affected =1.1.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until an official patch is released, organizations should consider disabling CSS Exfil Protection version 1.1.0 to eliminate the attack surface. If disabling is not feasible, restrict the extension’s permissions and monitor its activity closely. Implement network-level monitoring to detect unusual outbound traffic patterns that may indicate data exfiltration attempts via CSS channels. Employ Content Security Policy (CSP) headers to limit the ability of malicious CSS or scripts to execute or exfiltrate data. Conduct thorough audits of browser extensions and third-party tools to ensure they do not introduce vulnerabilities. Educate security teams about this specific vulnerability to enhance detection capabilities. Prepare to deploy patches promptly once available and verify their effectiveness through testing. Consider deploying endpoint detection and response (EDR) solutions capable of identifying anomalous behaviors related to CSS parsing and data exfiltration. Maintain up-to-date inventories of browser extensions and their versions to facilitate rapid response to similar future vulnerabilities.

Description

An issue in CSS Exfil Protection v.1.1.0 allows a remote attacker to obtain sensitive information via the content.js and parseCSSRules functions.

Impact

The primary impact of CVE-2024-29384 is unauthorized disclosure of sensitive information, which can lead to data breaches, privacy violations, and potential exposure of confidential organizational data. Since the vulnerability does not affect integrity or availability, it does not allow attackers to modify or disrupt systems directly, but the confidentiality breach alone can have severe consequences, including reputational damage, regulatory penalties, and loss of customer trust. Organizations relying on CSS Exfil Protection to secure their web environments may have a false sense of security, increasing risk exposure. The ease of exploitation and lack of required privileges mean that attackers can remotely target vulnerable systems at scale. This vulnerability could be leveraged as part of a broader attack chain to gather intelligence or facilitate further exploitation. The absence of patches increases the window of exposure, emphasizing the need for immediate mitigation. Industries handling sensitive data such as finance, healthcare, and government are particularly at risk due to the potential sensitivity of the leaked information.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #20OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
ICMP Echo Request Ping (opens in a new tab)
TCP SYN Scan (opens in a new tab)
Enumerate Mail Exchange (MX) Records (opens in a new tab)
DNS Zone Transfers (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 26 Feb 2026, 17:12 UTC

WeaknessesCWE-200

Technical details

References

Community reviews

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