Multiple vulnerabilities in Mozilla Firefox

1) Use-after-free

EUVDB-ID: #VU58609

Risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-4128

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when transitioning in and out of fullscreen mode. A remote attacker can trick the victim to visit a specially crafted website, trigger a use-after-free error and execute arbitrary code on the system.

Note, the vulnerability affects Firefox installations on macOS only.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Information disclosure

EUVDB-ID: #VU58585

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-43536

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to URL leakage when executing asynchronous functions. A remote attacker can trick the victim to open a specially crafted web page and reveal the URL of the page that is being visited afterwards.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Firefox ESR: 91.0 - 91.3.0

Mozilla Firefox: 90.0 - 94.0.2

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Type conversion

EUVDB-ID: #VU58586

Risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-43537

CWE-ID: CWE-704 - Type conversion

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to a type conversion error when processing sizes from 64bit to 32bit integers when using structured clone. A remote attacker can trick the victim to visit a specially crafted web page, trigger a heap-based buffer overflow and execute arbitrary code on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

4) Spoofing attack

EUVDB-ID: #VU58607

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-43538

CWE-ID: CWE-451 - User Interface (UI) Misrepresentation of Critical Information (Clickjacking, spoofing)

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to a race in notification code. A remote attacker can hide the notification for pages that had received full screen and pointer lock access. Successful exploitation of the vulnerability may allow an attacker to perform spoofing attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

5) Use-after-free

EUVDB-ID: #VU58608

Risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-43539

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error in GC rooting when calling wasm instance methods. A remote attacker can trick the victim to open a specially crafted web page, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

6) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU58610

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-43540

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to an error with WebExtensions that causes a WebExtension with the correct permissions to create and install ServiceWorkers for third-party websites that cannot be uninstalled with the extension.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

7) Input validation error

EUVDB-ID: #VU58611

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-43541

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to insufficient validation of user-supplied input when handling spaces in URLS with external protocol handlers. A remote attacker can trick the victim to click on a specially crafted link and pass unescaped input to a third-party application via URI handler.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

8) Information disclosure

EUVDB-ID: #VU58612

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-43542

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to the way Firefox handles XMLHttpRequest requests. A remote attacker can initiate a XMLHttpRequest and identify installed applications by probing error messages for loading external protocols.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

9) Security features bypass

EUVDB-ID: #VU58613

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-43543

CWE-ID: CWE-254 - Security Features

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to an error when handling CSP policies. Documents loaded with the CSP sandbox directive can escape the sandbox's script restriction by embedding additional content.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

10) Input validation error

EUVDB-ID: #VU58614

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-43544

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to insufficient validation of user-supplied input, when receiving a URL through a SEND intent. A remote attacker can trick the application to search for the specially crafted text, however subsequent usages of the address bar might caused the URL to load unintentionally, leading to XSS or spoofing attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Firefox for Android: 90.1.0 - 94.1.2

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

11) Infinite loop

EUVDB-ID: #VU58615

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-43545

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop when using Location API. A remote attacker can consume all available system resources and cause denial of service conditions.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

12) Spoofing attack

EUVDB-ID: #VU58616

Risk: Low

CVSSv4.0: 0.5 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-43546

CWE-ID: CWE-451 - User Interface (UI) Misrepresentation of Critical Information (Clickjacking, spoofing)

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to incorrect processing of user-supplied data, when native cursor is zoomed. A remote attacker can perform cursor spoofing attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

13) Buffer overflow

EUVDB-ID: #VU58617

Risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-4129

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing HTML content. A remote attacker can create a specially crafted website, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 90.0 - 94.0.2

Firefox ESR: 91.0 - 91.3.0

CPE2.3

External links

https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

Risk	High
Patch available	YES
Number of vulnerabilities	13
CVE-ID	CVE-2021-4128 CVE-2021-43536 CVE-2021-43537 CVE-2021-43538 CVE-2021-43539 CVE-2021-43540 CVE-2021-43541 CVE-2021-43542 CVE-2021-43543 CVE-2021-43544 CVE-2021-43545 CVE-2021-43546 CVE-2021-4129
CWE-ID	CWE-416 CWE-200 CWE-704 CWE-451 CWE-264 CWE-20 CWE-254 CWE-835 CWE-119
Exploitation vector	Network
Public exploit	N/A
Vulnerable software	Mozilla Firefox Client/Desktop applications / Web browsers Firefox ESR Client/Desktop applications / Web browsers Firefox for Android Mobile applications / Apps for mobile phones
Vendor	Mozilla