CVE-2024-7519 Overview
CVE-2024-7519 is a memory corruption vulnerability affecting Mozilla Firefox, Firefox ESR, and Thunderbird. The flaw originates from insufficient validation when processing graphics shared memory between browser processes. An attacker can leverage the resulting memory corruption to escape the browser sandbox, breaching one of the core security boundaries protecting the host operating system from web content. The vulnerability is classified as an out-of-bounds write [CWE-787] and requires user interaction, typically by visiting a malicious page. Mozilla patched the issue in Firefox 129, Firefox ESR 115.14, Firefox ESR 128.1, Thunderbird 115.14, and Thunderbird 128.1.
Critical Impact
Successful exploitation enables sandbox escape from the Firefox content process, allowing attackers to execute code outside the restricted renderer and target the underlying operating system.
Affected Products
- Mozilla Firefox versions prior to 129
- Mozilla Firefox ESR versions prior to 115.14 and prior to 128.1
- Mozilla Thunderbird versions prior to 115.14 and prior to 128.1
Discovery Timeline
- 2024-08-06 - CVE-2024-7519 published to NVD
- 2024-08-12 - Last updated in NVD database
Technical Details for CVE-2024-7519
Vulnerability Analysis
The vulnerability resides in Firefox's graphics subsystem, which uses shared memory regions to pass rendering data between the sandboxed content process and the privileged parent process. The code processing these shared memory buffers performs insufficient validation on attacker-influenced inputs. This creates an out-of-bounds write condition tracked as [CWE-787], allowing memory corruption inside a process running with higher privileges than the renderer.
Because the corruption occurs across a trust boundary, exploitation chains the bug with a content-process compromise to achieve a full sandbox escape. The CVSS scope change reflects this cross-boundary impact: code originally confined to the renderer reaches the parent process address space. Mozilla rated the issue with high confidentiality, integrity, and availability impact in security advisories MFSA-2024-33 through MFSA-2024-38.
Root Cause
The root cause is missing or inadequate bounds checking when the graphics code parses shared memory structures supplied by a lower-privilege process. An attacker who controls the contents and metadata of a shared memory region can craft values that cause the receiving code to read or write outside the intended buffer boundaries. Technical specifics are tracked in Mozilla Bug Report #1902307, which remains access-restricted pending wider patch adoption.
Attack Vector
Exploitation requires an attacker to deliver malicious web content to a vulnerable Firefox or Thunderbird build. The attacker first achieves code execution or memory manipulation inside the content process through additional vectors such as a JavaScript engine bug or a separately exploitable renderer flaw. The attacker then crafts a malformed shared memory payload that, when consumed by the parent process graphics code, triggers the out-of-bounds write. The resulting corruption is used to hijack control flow in the parent process, escaping the sandbox. User interaction is required, consistent with a drive-by browsing scenario.
Detection Methods for CVE-2024-7519
Indicators of Compromise
- Firefox or Thunderbird child process crashes referencing graphics or IPC shared memory handlers in crash telemetry.
- Unexpected spawning of shell or scripting interpreters as child processes of firefox.exe, firefox, or thunderbird binaries.
- Outbound network connections from a Firefox parent process to untrusted hosts following a browsing session.
Detection Strategies
- Inventory installed browser builds and flag any Firefox version below 129, Firefox ESR below 115.14 or 128.1, and Thunderbird below 115.14 or 128.1.
- Monitor endpoint process trees for anomalous descendants of the Firefox parent process, since sandbox escapes typically produce child processes the renderer should not create.
- Correlate browser crash events with subsequent privileged file or registry modifications to identify post-exploitation activity.
Monitoring Recommendations
- Forward browser process telemetry, including command lines and parent-child relationships, to a centralized analytics platform for behavioral review.
- Track Mozilla advisory feeds and software inventory data to confirm patch coverage across managed endpoints.
- Alert on Firefox or Thunderbird processes loading unexpected modules or executing code from writable memory regions.
How to Mitigate CVE-2024-7519
Immediate Actions Required
- Upgrade Firefox to version 129 or later on all managed endpoints.
- Upgrade Firefox ESR to 115.14 or 128.1 depending on the deployed channel.
- Upgrade Thunderbird to 115.14 or 128.1 to remediate the same flaw in the mail client's rendering stack.
- Restart browser and mail client processes after patching to ensure the vulnerable binaries are unloaded.
Patch Information
Mozilla shipped fixes in Firefox 129, Firefox ESR 115.14, Firefox ESR 128.1, Thunderbird 115.14, and Thunderbird 128.1. Full advisory details are available in Mozilla Security Advisory MFSA-2024-33, MFSA-2024-34, MFSA-2024-35, MFSA-2024-37, and MFSA-2024-38. Administrators using enterprise update channels should validate that automatic updates have applied the fixed builds.
Workarounds
- No vendor-supplied workaround exists; patching is the only supported remediation.
- Restrict browsing on unpatched systems to trusted internal sites until updates are deployed.
- Enforce least-privilege user accounts to limit the post-escape impact if exploitation occurs before patching.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
