CVE-2026-0847
Path Traversal in nltk/nltk
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List
7.5
Path Traversal in nltk/nltk
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
CVE-2026-0847- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Weakness
- CWE-22, CWE-22
- Updated
- 2026-11-02
EUVDEUVD-2026-9475
7.5
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
EUVD-2026-9475- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-68j8-pq59-fqgm
8.6
NLTK has a Path Traversal issue
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
GHSA-68j8-pq59-fqgm- CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Weakness
- CWE-22
- Updated
- 2026-11-04
NVD
7.5
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
CVE-2026-0847- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Weakness
- CWE-22
- Updated
- 2026-11-02
OSV
7.5
Path Traversal in nltk/nltk
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
CVE-2026-0847- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-0847
7.5
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
DEBIAN-CVE-2026-0847- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
Show 5 moreShow less
OSVGHSA-68j8-pq59-fqgm
8.6
NLTK has a Path Traversal issue
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
GHSA-68j8-pq59-fqgm- CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Weakness
- CWE-22
- Updated
- 2026-11-04
OSVPYSEC-2026-98
7.5
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
PYSEC-2026-98- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-0847
7.5
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
- Record
UBUNTU-CVE-2026-0847- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Updated
- 2026-11-02
OSVMGASA-2026-0057 No score
Updated python-nltk packages fix security vulnerability
Path Traversal in nltk/nltk. (CVE-2026-0847)
- Record
MGASA-2026-0057- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:10304-1 No score
python311-nltk-3.9.3-1.1 on GA media
These are all security issues fixed in the python311-nltk-3.9.3-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:10304-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
nltkPyPI |
through 3.9.2 | 3.9.3 |
nltkDebian:12 |
All versions, plus listed versions 3.10.0-13.10.1-13.10.3-13.8-13.8.1-1 Show 4 moreShow less3.9.1-13.9.1-23.9.2-13.9.3-1 |
None known |
nltkDebian:13 |
All versions, plus listed versions 3.10.0-13.10.1-13.10.3-13.9.1-23.9.2-13.9.3-1 |
None known |
nltkDebian:14 |
before 3.9.3-1, plus listed versions 3.9.1-23.9.2-1 |
3.9.3-1 |
nltkPyPI |
before 3.9.3, plus listed versions 0.80.90.9.30.9.40.9.5 Show 45 moreShow less0.9.60.9.70.9.80.9.92.0.12.0.1rc12.0.1rc2-git2.0.1rc32.0.1rc42.0.22.0.32.0.42.0.52.0b42.0b52.0b62.0b72.0b82.0b93.0.03.0.0b13.0.0b23.0.13.0.23.0.33.0.43.0.53.13.23.2.13.2.23.2.33.2.43.2.53.33.43.4.13.4.23.4.33.4.43.4.53.53.5b13.63.6.1 |
3.9.3 |
python-nltkMageia:9 |
before 3.9.3-1.mga9 | 3.9.3-1.mga9 |
nltkUbuntu:Pro:14.04:LTS |
before 2.0~b9-0ubuntu4.1~esm6, plus listed versions 2.0~b9-0ubuntu42.0~b9-0ubuntu4.1~esm22.0~b9-0ubuntu4.1~esm42.0~b9-0ubuntu4.1~esm5 |
2.0~b9-0ubuntu4.1~esm6 |
nltkUbuntu:Pro:16.04:LTS |
before 3.1-1ubuntu0.1+esm4, plus listed versions 3.0.4-13.0.5-13.1-13.1-1ubuntu0.13.1-1ubuntu0.1+esm13.1-1ubuntu0.1+esm23.1-1ubuntu0.1+esm3 |
3.1-1ubuntu0.1+esm4 |
nltkUbuntu:Pro:18.04:LTS |
before 3.2.5-1ubuntu0.1+esm4, plus listed versions 3.2.4-13.2.5-13.2.5-1ubuntu0.13.2.5-1ubuntu0.1+esm13.2.5-1ubuntu0.1+esm23.2.5-1ubuntu0.1+esm3 |
3.2.5-1ubuntu0.1+esm4 |
nltkUbuntu:Pro:20.04:LTS |
before 3.4.5-2ubuntu0.1~esm4, plus listed versions 3.4.5-13.4.5-23.4.5-2ubuntu0.1~esm13.4.5-2ubuntu0.1~esm23.4.5-2ubuntu0.1~esm3 |
3.4.5-2ubuntu0.1~esm4 |
Show 6 moreShow less
| Package | Affected | Fixed |
|---|---|---|
nltkUbuntu:Pro:22.04:LTS |
before 3.7-1ubuntu0.1~esm2, plus listed versions 3.5-13.6.5-13.6.7-13.7-13.7-1ubuntu0.1~esm1 |
3.7-1ubuntu0.1~esm2 |
nltkUbuntu:Pro:24.04:LTS |
before 3.8.1-1ubuntu0.1~esm2, plus listed versions 3.8.1-13.8.1-1ubuntu0.1~esm1 |
3.8.1-1ubuntu0.1~esm2 |
nltkUbuntu:25.10 |
All versions, plus listed versions 3.9.1-2 |
None known |
nltkUbuntu:26.10 |
All versions, plus listed versions 3.9.2-13.9.3-13.10.0-13.10.1-13.10.3-1 |
None known |
nltkUbuntu:Pro:26.04:LTS |
before 3.9.2-1ubuntu0.1~esm2, plus listed versions 3.9.1-23.9.1-2build13.9.2-13.9.2-1ubuntu0.1~esm1 |
3.9.2-1ubuntu0.1~esm2 |
python-nltkopenSUSE:Tumbleweed |
before 3.9.3-1.1 | 3.9.3-1.1 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | HyperPS/CVE-2026-0847 | 2026-03-29 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, references | OSV | |
| affected, facts | GitHub Advisories | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-0847 is a high vulnerability (CVSS 8.6) in Nltk, published March 4, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.00%, the 63rd percentile. Fixed in nltk 3.9.3.
References
huntr.com/bounties/fc69914f-36a9-4c18-8503-10013b39f966
access.redhat.com/security/cve/CVE-2026-0847
bugzilla.redhat.com/show_bug.cgi?id=2444608
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-0847.json
access.redhat.com/errata/RHSA-2026:10184
access.redhat.com/errata/RHSA-2026:19712
Show 16 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-0847
github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-98.yaml
github.com/advisories/GHSA-68j8-pq59-fqgm
github.com/CVEProject/cvelistV5/tree/main/cves/2026/0xxx/CVE-2026-0847.json
security-tracker.debian.org/tracker/CVE-2026-0847
github.com/nltk/nltk
advisories.mageia.org/MGASA-2026-0057.html
bugs.mageia.org/show_bug.cgi?id=35188
lists.opensuse.org/archives/list/[email protected]/message/UERV2PU6W5DFFKA4ORZASCPJ2ZDGYTBX
ubuntu.com/security/CVE-2026-0847
cve.org/CVERecord?id=CVE-2026-0847
huntr.com/bounties/fc69914f-36a9-4c18-8503-10013b39f96
github.com/nltk/nltk/pull/3479
github.com/nltk/nltk/commit/603e34d25a2cad4612185ebfa6bc1c0dcfcfb2ab
ubuntu.com/security/notices/USN-8302-1
suse.com/security/cve/CVE-2026-0847
Left out here: 13 versions. The JSON record has them.