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| Vulnerability ID | VCID-9e28-p8t5-aaak |
| Aliases |
CVE-2020-26950
|
| Summary | In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2. |
| Status | Published |
| Exploitability | 2.0 |
| Weighted Severity | 9.0 |
| Risk | 10.0 |
| Affected and Fixed Packages | Package Details |
| CWE-416 | Use After Free |
| Data source | Metasploit |
|---|---|
| Description | This modules exploits CVE-2020-26950, a use after free exploit in Firefox. The MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This exploit uses a somewhat novel technique of spraying ArgumentsData structures in order to construct primitives. The shellcode is forced into executable memory via the JIT compiler, and executed by writing to the JIT region pointer. This exploit does not contain a sandbox escape, so firefox must be run with the MOZ_DISABLE_CONTENT_SANDBOX environment variable set, in order for the shellcode to run successfully. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2, however only Firefox <= 79 is supported as a target. Additional work may be needed to support other versions such as Firefox 82.0.1. |
| Note | Reliability: - repeatable-session SideEffects: - ioc-in-logs Stability: - crash-safe |
| Ransomware campaign use | Unknown |
| Source publication date | Nov. 18, 2020 |
| Platform | Linux,Windows |
| Source URL | https://github.com/rapid7/metasploit-framework/tree/master/modules/exploits/multi/browser/firefox_jit_use_after_free.rb |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Exploitability (E) | Access Vector (AV) | Access Complexity (AC) | Authentication (Au) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|
high functional unproven proof_of_concept not_defined |
local adjacent_network network |
high medium low |
multiple single none |
none partial complete |
none partial complete |
none partial complete |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Percentile | 0.97845 |
| EPSS Score | 0.55139 |
| Published At | March 28, 2025, 12:55 p.m. |
| Date | Actor | Action | Source | VulnerableCode Version |
|---|---|---|---|---|
| There are no relevant records. | ||||