Arbitrary file write via intermediate symlink traversal
Published Jul 21, 2026 · Updated Jul 21, 2026
Path traversal in Sparkle before 2.9.2 allows attackers to write arbitrary files via a signed malicious binary delta. The delta extractor accepts symlink targets verbatim, checks only the immediate parent, then opens a later path through an intermediate symlink and writes outside the staging tree. Exploitation requires compromise of the developer's EdDSA private key and user interaction; system-domain installs expand the consequence to arbitrary root-level file writes.
Summary
What happened
Path traversal in Sparkle before 2.9.2 allows attackers to write arbitrary files via a signed malicious binary delta. The delta extractor accepts symlink targets verbatim, checks only the immediate parent, then opens a later path through an intermediate symlink and writes outside the staging tree. Exploitation requires compromise of the developer's EdDSA private key and user interaction; system-domain installs expand the consequence to arbitrary root-level file writes.
The record
- CVE
- CVE-2026-47121
- Published
- Jul 21, 2026
- Updated
- Jul 21, 2026
- Vendor
- Sparkle Project
- Product
- Sparkle
- Classifications
- CWE-22, CWE-59, T1195.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.9.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-hg88-v3cw-3qrh embedded proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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