Outside-root file disclosure via raw corpus opens
Published Aug 25, 2026 · Updated Aug 25, 2026
Path traversal in NLTK before 3.10.3 allows remote attackers to read outside-root files through symlinked corpus inputs. Several corpus readers convert trusted root-derived paths to strings and reopen them with built-in open() instead of the symlink-aware nltk.pathsec.open(). Exploitation requires control of corpus files or symlinks under a trusted data root, and disclosure is limited to files readable by the application process.
Summary
What happened
Path traversal in NLTK before 3.10.3 allows remote attackers to read outside-root files through symlinked corpus inputs. Several corpus readers convert trusted root-derived paths to strings and reopen them with built-in open() instead of the symlink-aware nltk.pathsec.open(). Exploitation requires control of corpus files or symlinks under a trusted data root, and disclosure is limited to files readable by the application process.
The record
- CVE
- CVE-2026-79676
- Published
- Aug 25, 2026
- Updated
- Aug 25, 2026
- Vendor
- NLTK Project
- Product
- NLTK
- Classifications
- CWE-59, CWE-22, T1005
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 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=0 <3.10.3
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
- Upstream symlink-escape proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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