Medium File handling exploit reference

CVE-2026-62383 — nltk IPIPANCorpusReader Symlink Arbitrary File Read

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.

Published Aug 22, 2026 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: VulnCheck

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.18%

ahead of 7% of scored CVEs · Oct 14, 2026

Affects

Nltk

CVSS base

5.5

Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented mitigation — github.com (NIST National Vulnerability Database)
Pip Nltk: fixed in version 3.10.2 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Nltk Nltk, Pip Nltk).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Nltk	Nltk	≥ 3.10.0 and < 3.10.2	Vulnerable	NIST National Vulnerability Database
Nltk	Nltk	≥ 3.10.0 and < 3.10.2	Vulnerable	CVE Program (cve.org) e CISA ADP
Pip	Nltk	≥ 3.10.0 and < 3.10.2	Vulnerable	GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
6.8	CVSS 4.0	Medium	—	—	disclosure@vulncheck.com via NIST National Vulnerability Database
6.8	CVSS 4.0	Medium	—	—	VulnCheck via CVE Program (cve.org) e CISA ADP
5.5	CVSS 3.1	Medium	1.8	3.6	disclosure@vulncheck.com via NIST National Vulnerability Database
5.5	CVSS 3.1	Medium	—	—	GitHub, Inc. via GitHub Security Advisories
5.5	CVSS 3.1	Medium	—	—	VulnCheck via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N (score shown at the top: disclosure@vulncheck.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-22 · Path Traversal

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.18%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Monitor file creation in web directories and paths with traversal sequences (../).

endpoint telemetry (EDR)file integrity (FIM)

Timeline

What happened to this CVE, newest first.

2026
Fix documented
Oct 14, 2026 · GitHub Security Advisories
Affected products added · pip/nltk
Oct 14, 2026 · GitHub Security Advisories
Affected products added · nltk/nltk
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 14, 2026
Fix documented
Oct 14, 2026 · NIST National Vulnerability Database
Affected products added · nltk/nltk
Oct 14, 2026 · NIST National Vulnerability Database
CVSS changed · 5.5
Oct 14, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 14, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 14, 2026 · Alertas do Telegram
CVE published
Aug 22, 2026 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

2× References added · Oct 14, 2026 – Oct 14, 2026
1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

8 on the record

github.com/nltk/nltk/security/advisories/GHSA-3hhw-38pf-pxj6
Exploit, Mitigation, Vendor Advisory, vendor-advisory, NIST National Vulnerability Database
github.com/nltk/nltk/pull/3727
GitHub Security Advisories
nvd.nist.gov/vuln/detail/CVE-2026-62383
GitHub Security Advisories
www.vulncheck.com/advisories/nltk-ipipancorpusreader-symlink-arbitrary-file-read
Third Party Advisory, third-party-advisory, NIST National Vulnerability Database
github.com/nltk/nltk/commit/ee1a42e51982c4dce6ad3ee77ff1ac43894288ab
GitHub Security Advisories
github.com/advisories/GHSA-3hhw-38pf-pxj6
GitHub Security Advisories
github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3726.yaml
GitHub Security Advisories
github.com/nltk/nltk/releases/tag/v3.10.2
GitHub Security Advisories

Elsewhere on this site

Nltk
every CVE for this vendor

File handling
same class

CWE-22
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-109956 NLTK through 3.10.3 Path Traversal via WekaClassifier Model Path 2d
High CVE-2026-81726 NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that… Aug 27, 2026
Low CVE-2026-81725 Uncontrolled Resource Consumption in Nltk Aug 27, 2026
Medium CVE-2026-81724 Uncontrolled Recursion in Nltk Aug 27, 2026
High CVE-2026-81727 Link Following in Nltk Aug 27, 2026
High CVE-2026-81722 nltk PorterStemmer in versions Aug 27, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-62383 is "nltk IPIPANCorpusReader Symlink Arbitrary File Read", rated Medium. It affects Nltk (Nltk); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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