Summary
Sparkle: Binary delta apply intermediate-symlink traversal in malicious .delta
Impact
Defense-in-depth gap: the holder of a compromised EdDSA signing key gains a primitive (arbitrary file write at the privilege of the AppInstaller process) that exceeds what an "install a malicious bundle" path provides. For system-domain installs this is arbitrary file write as root, including locations outside the target app bundle (/Library/LaunchDaemons, /etc/... subpaths that exist as directories, /usr/local/, etc.).
Recommended fix: in SUBinaryDeltaApply.m, walk every component of relativePath and reject if any intermediate component is a symlink (or refuse to allow the archive to create symlinks during apply at all, given the limited number of legitimate use cases for symlinks inside an .app bundle and the existing lchmod already in place). Cleanup on failure should also removeTree along the symlink target, not just finalDestination.
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-47121 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
In the interim: Resolve the canonical path after applying any user-supplied input, and verify it remains within the intended directory before accessing it.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-47121? CVE-2026-47121 is a medium-severity path traversal vulnerability in github.com/sparkle-project/Sparkle (swift), affecting versions <= 2.9.1. No fixed version is listed yet. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-47121? CVE-2026-47121 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/sparkle-project/Sparkle are affected by CVE-2026-47121? github.com/sparkle-project/Sparkle (swift) versions <= 2.9.1 is affected.
- Is there a fix for CVE-2026-47121? No fixed version is listed for CVE-2026-47121 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2026-47121 exploitable, and should I be worried? Whether CVE-2026-47121 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-47121 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-47121? No fixed version is listed yet. In the interim: Resolve the canonical path after applying any user-supplied input, and verify it remains within the intended directory before accessing it.