CVE-2026-12372: Gptline · NLTK network URL validation permits SSRF to RFC 6598 shared-address-space hosts
Affects gptlineSource GCVE Database
Not known to be exploited · CVSS 3.7 Low : upgrade to 1.0.8_22 when convenient.
Data as of 7 Nov 2026, 23:24 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.10.0, 3.8.1_1, 1.0.8_22
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.
What to do
Upgrade gptline to 1.0.8_22; nltk to 3.10.0; safety to 3.8.1_1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
PyPInltkpkg:pypi/nltkOther threats | Affected
| Fixed in– |
| PyPInltk | Affected
| Fixed in
|
Homebrewsafetypkg:brew/safetyOther threats | Affected
| Fixed in
|
Homebrewgptlinepkg:brew/gptlineOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available for this vulnerability. Users should upgrade to nltk version 3.10.0 or later where this issue is fixed. Until patched, avoid passing untrusted URLs to NLTK's network-loading helpers or validate URLs externally to block RFC 6598 shared address space IPs.
Description
A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The `nltk.pathsec.validate_network_url()` function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space (`100.64.0.0/10`). This occurs because Python's `ipaddress` module does not classify such addresses as `is_private` or `is_global`, and the current guard only checks `is_private` and a few explicit categories. An attacker who can influence a URL passed to NLTK's network-loading helpers can exploit this vulnerability to make a strict-mode application send requests to shared-address-space hosts, potentially exposing non-public infrastructure reachable from the application host. The impact is limited to SSRF-style confidentiality exposure, with no code execution claimed.
References
- nvd.nist.gov/vuln/detail/CVE-2026-12372 (opens in a new tab)
- huntr.com/bounties/2911b643-571c-42e4-b0c2-9a1fa6f491db (opens in a new tab)
- suse.com/support/security/rating/ (opens in a new tab)
- ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11510-1.json (opens in a new tab)
- suse.com/security/cve/CVE-2026-12372/ (opens in a new tab)
- github.com/nltk/nltk/commit/4a820afa58810cd05049b6c6eae306694d6cfe65 (opens in a new tab)
- github.com/nltk/nltk (opens in a new tab)
- github.com/nltk/nltk/releases/tag/v3.10.0 (opens in a new tab)
- github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3955.yaml (opens in a new tab)