CVE-2026-47121
Sparkle: Binary delta apply intermediate-symlink traversal in malicious .delta
Description
Sparkle is a software update framework for macOS. Prior to version 2.9.2, `Autoupdate/SUBinaryDeltaApply.m` enforces `relativePath.pathComponents containsObject:@".."` and rejects writes whose immediate parent directory IS itself a symbolic link, but does not detect symlinks deeper in the relative path. `Autoupdate/SPUSparkleDeltaArchive.m`'s `extractItem:` will create symlinks in the destination tree from archive content (no `..` check on the symlink target), and a subsequent `Extract` item targeting `<symlink>/foo/bar` then escapes the destination tree via `fopen(path, "wb")` because the kernel resolves the intermediate symlink during the open call. This is a defense-in-depth issue: exploitation requires a maliciously-crafted `.delta` that passes EdDSA signature verification, i.e. EdDSA private-key compromise. With the AppInstaller running as root for system-domain installs, it gives the holder of a stolen signing key arbitrary file write at root level via the delta-apply path, which is a strictly broader primitive than the "drop-in replacement bundle" install they would otherwise have. Version 2.9.2 contains a patch for the issue.
INFO
Published Date :
July 21, 2026, 2:16 p.m.
Last Modified :
Oct. 24, 2026, 8:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update Sparkle to version 2.9.2 or later.
- Apply vendor patches for Sparkle.
- Ensure archive extraction validates symlink targets.
- Verify integrity of update archives.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-47121.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-47121 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-47121
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-47121 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-47121 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Added Translation Title: Sparkle de sparkle-project, Description: Sparkle es un framework de actualización de software para macOS. Antes de la versión 2.9.2, ’Autoupdate/SUBinaryDeltaApply.m’ aplica ’relativePath.pathComponents containsObject:’..’ y rechaza escrituras cuyo directorio padre inmediato ES en sí mismo un enlace simbólico, pero no detecta enlaces simbólicos más profundos en la ruta relativa. El ’extractItem:’ de ’Autoupdate/SPUSparkleDeltaArchive.m’ creará enlaces simbólicos en el árbol de destino a partir del contenido del archivo (sin verificación de ’..’ en el objetivo del enlace simbólico), y un elemento ’Extract’ posterior que apunte a ’[symlink]/foo/bar’ escapará del árbol de destino a través de ’fopen(path, “wb”)’ porque el kernel resuelve el enlace simbólico intermedio durante la llamada de apertura. Este es un problema de defensa en profundidad: la explotación requiere un ’.delta’ manipulado maliciosamente que pase la verificación de firma EdDSA, es decir, el compromiso de la clave privada EdDSA. Con el AppInstaller ejecutándose como root para instalaciones de dominio del sistema, otorga al poseedor de una clave de firma robada la capacidad de escritura arbitraria de archivos a nivel de root a través de la ruta de aplicación de delta, lo cual es una primitiva estrictamente más amplia que la instalación de ’paquete de reemplazo directo’ que tendrían de otra manera. La versión 2.9.2 contiene un parche para el problema. -
Initial Analysis by [email protected]
Aug. 05, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:sparkle-project:sparkle:*:*:*:*:*:*:*:* versions up to (excluding) 2.9.2 Added Reference Type GitHub, Inc.: https://github.com/sparkle-project/Sparkle/commit/fe7b718d0736f3e139e374e26fbca96f29e13bf0 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/sparkle-project/Sparkle/security/advisories/GHSA-hg88-v3cw-3qrh Types: Vendor Advisory Added Reference Type CISA-ADP: https://github.com/sparkle-project/Sparkle/security/advisories/GHSA-hg88-v3cw-3qrh Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 22, 2026
Action Type Old Value New Value Added Reference https://github.com/sparkle-project/Sparkle/security/advisories/GHSA-hg88-v3cw-3qrh Added SSVC {'id': 'CVE-2026-47121', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-22T14:30:24.947456Z'} -
New CVE Received by [email protected]
Jul. 21, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'sparkle-project', 'product': 'Sparkle', 'versions': [{'status': 'affected', 'version': '< 2.9.2'}]}] Added Description Sparkle is a software update framework for macOS. Prior to version 2.9.2, `Autoupdate/SUBinaryDeltaApply.m` enforces `relativePath.pathComponents containsObject:@".."` and rejects writes whose immediate parent directory IS itself a symbolic link, but does not detect symlinks deeper in the relative path. `Autoupdate/SPUSparkleDeltaArchive.m`'s `extractItem:` will create symlinks in the destination tree from archive content (no `..` check on the symlink target), and a subsequent `Extract` item targeting `<symlink>/foo/bar` then escapes the destination tree via `fopen(path, "wb")` because the kernel resolves the intermediate symlink during the open call. This is a defense-in-depth issue: exploitation requires a maliciously-crafted `.delta` that passes EdDSA signature verification, i.e. EdDSA private-key compromise. With the AppInstaller running as root for system-domain installs, it gives the holder of a stolen signing key arbitrary file write at root level via the delta-apply path, which is a strictly broader primitive than the "drop-in replacement bundle" install they would otherwise have. Version 2.9.2 contains a patch for the issue. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N Added CWE CWE-22 Added CWE CWE-59 Added Reference https://github.com/sparkle-project/Sparkle/commit/fe7b718d0736f3e139e374e26fbca96f29e13bf0 Added Reference https://github.com/sparkle-project/Sparkle/security/advisories/GHSA-hg88-v3cw-3qrh