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CVE-2025-68161 — log4j-core

Fix: apache/logging-log4j2#4002

CVE-2025-68161 is a CWE-297 vulnerability in org.apache.logging.log4j:log4j-core. A fix is available for org.apache.logging.log4j:log4j-core — see the affected versions and patch details below.

Apache Log4j Core: Missing TLS hostname verification in Socket appender

Also known asGHSA-vc5p-v9hr-52mj
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-68161.

EPSS Exploitation Probability

via FIRST.org ↗
0.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs56th percentile — riskier than 56% of all scored CVEsHighest risk
0.00%0.44%0.88%1.32%0.0%0.8%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected
☕org.apache.logging.log4j:log4j-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.apache.logging.log4j:log4j-core≥ 2.0-beta9&&< 2.25.32.25.3org.apache.logging.log4j:log4j-core:2.25.3

Affected Products

1 product · 6 configurations
Application
log4japache
≥ 2.0.1 && < 2.25.3
1 version
2.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.logging.log4j:log4j-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.apache.logging.log4j:log4j-core to 2.25.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-68161 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

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
O3 Security · Impact-Aware SCA

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CVE-2025-68161: log4j-core — Fixed in 2.25.3