CVE-2026-50127 Weblate SSRF: outbound URL guard misses the NAT64 well-known prefix (64:ff9b::/96)
Attackers can bypass private IP restrictions in Weblate's VCS integration by exploiting missing IPv6 NAT64 prefix checks, enabling Server-Side Request Forgery.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-50127?
CVE-2026-50127 is a medium-severity server-side request forgery vulnerability in WeblateOrg weblate, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-918
Which versions are affected by CVE-2026-50127?
3 open source packages ship an affected version, including weblate.
| Package | Affected | Fixed in |
|---|---|---|
weblate PyPI | From 5.15 | 2026.6 |
weblate PyPI | From 5.15 | 2026.6 |
weblate PyPI | From 5.15 | 2026.6 |
How do I fix CVE-2026-50127?
Upgrade weblate to 2026.6 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-50127 being exploited?
There is no known exploitation of CVE-2026-50127 in the wild and no public exploit code.
Sources
Also known as GHSA-vmfc-9982-2m45, PYSEC-2026-3416.