# CVE-2019-11707: Mozilla Firefox and Thunderbird Type Confusion > A type confusion flaw in Firefox and Thunderbird allows attackers to cause crashes and potentially execute arbitrary code via crafted JavaScript. - **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Yes, since 23 May 2022 (CISA KEV) - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 23 Jul 2019 - **Updated:** 21 Oct 2025 - **Also known as:** ALPINE-CVE-2019-11707, DEBIAN-CVE-2019-11707, DLA-1829-1, DSA-4466-1, GHSA-8ffr-q7j8-h445, MGASA-2019-0198, SUSE-RU-2019:1625-1, SUSE-SU-2019:1629-1, UBUNTU-CVE-2019-11707, USN-4020-1, openSUSE-SU-2019:1593-1 ## What is CVE-2019-11707? CVE-2019-11707 is a high-severity memory corruption vulnerability in Mozilla Firefox, published on 23 Jul 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official description A type confusion vulnerability can occur when manipulating JavaScript objects due to issues in Array.pop. This can allow for an exploitable crash. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 60.7.1, Firefox < 67.0.3, and Thunderbird < 60.7.2. Weakness: CWE-843 (Access of Resource Using Incompatible Type) ## Which versions are affected by CVE-2019-11707? It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `MozillaFirefox` | SUSE:Enterprise Storage 4 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Desktop 12 SP3 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Desktop 12 SP4 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Module for Desktop Applications 15 | All versions | 60.7.1-3.45.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Module for Desktop Applications 15 SP1 | All versions | 60.7.1-3.45.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server 12 SP1-LTSS | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server 12 SP2-BCL | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server 12 SP2-LTSS | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server 12 SP3 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server 12 SP4 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server 12-LTSS | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server for SAP Applications 12 SP1 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server for SAP Applications 12 SP2 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Server for SAP Applications 12 SP4 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Software Development Kit 12 SP3 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:Linux Enterprise Software Development Kit 12 SP4 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | SUSE:OpenStack Cloud 7 | All versions | 60.7.1-109.77.1 | | `MozillaFirefox` | openSUSE:Leap 15.0 | All versions | 60.7.2-lp150.3.59.1 | Products: Mozilla Firefox, Mozilla Thunderbird. ## How do I fix CVE-2019-11707? Upgrade to a fixed version. US federal agencies must fix it by 13 Jun 2022. ## Is CVE-2019-11707 being exploited? Yes. Attackers have exploited CVE-2019-11707 in the wild since at least 23 May 2022. Public exploit code: - Exploit code for CVE-2019-11707 on Firefox 66.0.3 running on Ubuntu (github_poc): https://github.com/vigneshsrao/CVE-2019-11707 - https://bugs.chromium.org/p/project-zero/issues/detail?id=1820 (github_poc): https://github.com/flabbergastedbd/cve-2019-11707 - Mozilla Spidermonkey - IonMonkey 'Array.prototype.pop' Type Confusion (exploitdb) - Mozilla Firefox 67 - Array.pop JIT Type Confusion (exploitdb) - Proof of concept for CVE-2019-11707 (github_poc): https://github.com/CosminGGeorgescu/CVE-2019-11707-PoC - CVE-2019-11707 is a critical type confusion in Firefox's IonMonkey optimizing JIT. The browser bug provides native code execution in the content process, but that process remains constrained by the Firefox sandbox. The complete laboratory chain therefore combines three vulnerabilities: (github_poc): https://github.com/G4sp4rCS/CVE-2019-11707-from-an-IonMonkey-type-confusion-to-SYSTEM- ## Other vulnerabilities in Mozilla Firefox - [CVE-2019-11708](https://insights.sbomify.com/CVE-2019-11708/): Mozilla Firefox and Thunderbird Sandbox Escape (critical 10.0, exploited in the wild) - [CVE-2010-3765](https://insights.sbomify.com/CVE-2010-3765/): Mozilla Multiple Products Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2022-26486](https://insights.sbomify.com/CVE-2022-26486/): Mozilla Firefox Use-After-Free (critical 9.6, exploited in the wild) - [CVE-2022-26485](https://insights.sbomify.com/CVE-2022-26485/): Mozilla Firefox Use-After-Free (high 8.8, exploited in the wild) - [CVE-2020-6819](https://insights.sbomify.com/CVE-2020-6819/): Mozilla Firefox And Thunderbird Use-After-Free (high 8.1, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2019-11707 and fix it if it is affected. What it is: CVE-2019-11707 is a high-severity memory corruption vulnerability in Mozilla Firefox, published on 23 Jul 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: Yes. Attackers have exploited CVE-2019-11707 in the wild since at least 23 May 2022. Affected product: Mozilla Firefox. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2019-11707/ (Markdown: https://insights.sbomify.com/CVE-2019-11707/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2019-11707 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-11707 - OSV: https://osv.dev/vulnerability/CVE-2019-11707 --- From sbomify Insights: https://insights.sbomify.com/CVE-2019-11707/ Summaries are generated and may contain mistakes; the official description above is the record.