DEBIAN-CVE-2026-63311

Source
https://security-tracker.debian.org/tracker/CVE-2026-63311
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63311.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-63311
Upstream
Published
2026-08-22T15:16:19Z
Modified
2026-09-14T17:03:11Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L/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 before 3.10.0 (affected versions <= 3.9.4) contains a server-side request forgery (SSRF) vulnerability in the validate_network_url() function in nltk/pathsec.py. The _resolve_hostname() helper catches OSError and ValueError during socket.getaddrinfo() and returns an empty list; when DNS resolution fails, the validation loop executes no IP checks and the function fails open, allowing urlopen() to proceed without validation. An attacker who can trigger DNS resolution failures or use DNS rebinding can bypass SSRF protections and reach restricted network resources, including cloud metadata endpoints (e.g., 169.254.169.254).

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-2026-63311.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-2026-63311.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
3.10.0-1

Affected versions

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

Ecosystem specific

{
    "urgency":  "not yet assigned"
}

Database specific

source
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63311.json"