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CVE-2026-47121— Sparkle: Binary delta apply intermediate-symlink traversal in malicious .delta

Quick assessment

Affected
sparkle-project Sparkle
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

sparkle-project sparkle是sparkle-project团队开源的一个软件更新框架。 sparkle-project sparkle 2.9.2之前版本存在安全漏洞，该漏洞源于SUBinaryDeltaApply.m对相对路径中的符号链接检测不足，且SPUSparkleDeltaArchive.m在提取归档内容时会创建符号链接，导致攻击者通过特制.delta文件利用符号链接逃逸目标目录，实现任意文件写入。

CVSS 6.1 · Medium EPSS 0.34% · P26

Affected Version Matrix 1

VendorProduct Version RangeStatus
sparkle-project Sparkle < 2.9.2 affected
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I. Basic Information for CVE-2026-47121

Vulnerability Information
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Vulnerability Title
Sparkle: Binary delta apply intermediate-symlink traversal in malicious .delta
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5
Vulnerability Title
sparkle-project sparkle 路径遍历漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
sparkle-project sparkle是sparkle-project团队开源的一个软件更新框架。 sparkle-project sparkle 2.9.2之前版本存在安全漏洞，该漏洞源于SUBinaryDeltaApply.m对相对路径中的符号链接检测不足，且SPUSparkleDeltaArchive.m在提取归档内容时会创建符号链接，导致攻击者通过特制.delta文件利用符号链接逃逸目标目录，实现任意文件写入。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
sparkle-project Sparkle < 2.9.2 -

II. Public POCs for CVE-2026-47121

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III. Intelligence Information for CVE-2026-47121

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Patches & Fixes for CVE-2026-47121 (1)

Vendor Advisories for CVE-2026-47121 (1)

IV. Related Vulnerabilities

Same product: Sparkle
Same vendor: sparkle-project
Same weakness: CWE-22

V. Comments for CVE-2026-47121

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