---
cve: "CVE-2026-47121"
severity: "MEDIUM"
cvss: 6.1
epss: "0.3%"
vendor: "sparkle-project"
kev: false
exploited: false
published: "2026-07-21 14:16:34"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T13:20:04+02:00"
---

# CVE-2026-47121

> 6.1 MEDIUM · 🧪 PoC

## Beschreibung

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 `/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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Erforderlich | good |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Keine | good |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 6276ba2b404829d139c45ff98427cf90e2efc59b (Commit)
- fe7b718d0736f3e139e374e26fbca96f29e13bf0 (Commit)

## Referenzen

- <https://github.com/sparkle-project/Sparkle/security/advisories/GHSA-hg88-v3cw-3qrh>
- <https://github.com/sparkle-project/Sparkle/commit/fe7b718d0736f3e139e374e26fbca96f29e13bf0>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-47121) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_