# CVE-2026-62383: nltk IPIPANCorpusReader Symlink Arbitrary File Read

> Attackers can read arbitrary files by placing symlinks in the corpus directory, bypassing security checks in the nltk library.

- **Severity:** Medium 6.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-62383, GHSA-3hhw-38pf-pxj6, PYSEC-2026-3726, UBUNTU-CVE-2026-62383

## What is CVE-2026-62383?

CVE-2026-62383 is a medium-severity path traversal vulnerability in nltk, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

nltk versions before 3.10.2 contain a symlink-based arbitrary file read vulnerability in IPIPANCorpusReader methods that bypass nltk.pathsec validation entirely. Attackers can place a symlink in the corpus root directory and read arbitrary files accessible to the process by calling channels(), domains(), categories(), or fileids() methods with the symlink filename.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-62383?

3 open source packages ship an affected version, including nltk. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nltk` | PyPI | From 3.10.0 | 3.10.2 |
| `nltk` | PyPI | From 3.10.0 | 3.10.2 |
| `nltk` | PyPI | From 3.10.0 | 3.10.2 |

Products: Nltk Nltk.

## How do I fix CVE-2026-62383?

Upgrade nltk to 3.10.2 or later.

## Is CVE-2026-62383 being exploited?

There is no known exploitation of CVE-2026-62383 in the wild and no public exploit code.

## Other vulnerabilities in nltk

- [CVE-2026-0848](https://insights.sbomify.com/CVE-2026-0848/): Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading (critical 10.0)
- [CVE-2025-14009](https://insights.sbomify.com/CVE-2025-14009/): Zip Slip Vulnerability in nltk/nltk Leading to Remote Code Execution (critical 10.0)
- [CVE-2026-78683](https://insights.sbomify.com/CVE-2026-78683/): NLTK before 3.10.0 Remote Code Execution via Unsafe Pickle Deserialization (critical 9.4)
- [CVE-2026-79657](https://insights.sbomify.com/CVE-2026-79657/): NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization (critical 9.3)
- [CVE-2026-79675](https://insights.sbomify.com/CVE-2026-79675/): NLTK before 3.10.3 JVM Argument Injection via Per-Call Options (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62383 and fix it if it is affected.

What it is: CVE-2026-62383 is a medium-severity path traversal vulnerability in nltk, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-62383 in the wild and no public exploit code.

Affected packages and fixed versions:
- nltk (PyPI): affected from 3.10.0; fixed in 3.10.2
- nltk (PyPI): affected from 3.10.0; fixed in 3.10.2
- nltk (PyPI): affected from 3.10.0; fixed in 3.10.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-62383/ (Markdown: https://insights.sbomify.com/CVE-2026-62383/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62383
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62383
- OSV: https://osv.dev/vulnerability/CVE-2026-62383

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62383/
Summaries are generated and may contain mistakes; the official description above is the record.