CVE-2021-42550Public exploitNetwork attack vector

Code execution via unrestricted JNDI configuration lookup

Published Dec 16, 2021 · Updated Aug 4, 2024

JNDI injection in QOS.ch Sarl Logback before 1.2.9 and before 1.3.0-alpha11 allows attackers to execute code loaded from LDAP servers. JNDIUtil.lookup passes configuration-supplied names to Context.lookup without restricting them to the local java: namespace. Exploitation requires write access to logback.xml and either an application restart or pre-enabled automatic configuration scanning.

CVSS severity6.6
Medium
EPSS probability4.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

JNDI injection in QOS.ch Sarl Logback before 1.2.9 and before 1.3.0-alpha11 allows attackers to execute code loaded from LDAP servers. JNDIUtil.lookup passes configuration-supplied names to Context.lookup without restricting them to the local java: namespace. Exploitation requires write access to logback.xml and either an application restart or pre-enabled automatic configuration scanning.

The record

CVE
CVE-2021-42550
Published
Dec 16, 2021
Updated
Aug 4, 2024
Vendor
QOS.ch Sarl
Product
Logback
Classifications
CWE-502
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Dec 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <1.2.9
  2. Affected versionversion=unspecified <1.3.0-alpha11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

QOS.ch Sarl · Logbackversion=unspecified <1.2.9; version=unspecified <1.3.0-alpha11

Published CVSS scores

6.6GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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