DEBIAN-CVE-2026-81727

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Source
https://security-tracker.debian.org/tracker/CVE-2026-81727
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-81727.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-81727
Upstream
Published
2026-08-27T17:21:03Z
Modified
2026-09-14T17:03:49Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X CVSS Calculator
Summary
[none]
Details

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incr_download methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader directory can create hardlinks pointing to outside-root files that are then overwritten during normal package extraction, mutating files outside the intended install tree.

References

Affected packages

Debian:12 / nltk

Package

Name
nltk
Purl
pkg:deb/debian/nltk?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.8-1
3.8.1-1
3.9.1-1
3.9.1-2
3.9.2-1
3.9.3-1
3.10.0-1
3.10.1-1
3.10.3-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-81727.json"

Debian:13 / nltk

Package

Name
nltk
Purl
pkg:deb/debian/nltk?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.9.1-2
3.9.2-1
3.9.3-1
3.10.0-1
3.10.1-1
3.10.3-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-81727.json"

Debian:14 / nltk

Package

Name
nltk
Purl
pkg:deb/debian/nltk?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.10.3-1

Affected versions

3.*
3.9.1-2
3.9.2-1
3.9.3-1
3.10.0-1
3.10.1-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-81727.json"