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CVE-2025-54812

Apache Log4cxx: Improper HTML escaping in HTMLLayout

2.1 LowFix available

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx.

When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur:

  • Log4cxx is configured to use HTMLLayout.

  • Logger name comes from an untrusted string

  • Logger with compromised name logs a message

  • User opens the generated HTML log file in their browser, leading to potential XSS

Because logger names are generally constant strings, we assess the impact to users as LOW

This issue affects Apache Log4cxx: before 1.5.0.

Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
Active

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
None

Exploit likelihood

1.24%Up 1.2 points since Aug 23, 2025
90%50%10%1%

What each source reports

CVE List Score used 2.1

Apache Log4cxx: Improper HTML escaping in HTMLLayout

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx.

When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur:

  • Log4cxx is configured to use HTMLLayout.

  • Logger name comes from an untrusted string

  • Logger with compromised name logs a message

  • User opens the generated HTML log file in their browser, leading to potential XSS

Because logger names are generally constant strings, we assess the impact to users as LOW

This issue affects Apache Log4cxx: before 1.5.0.

Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Record
CVE-2025-54812
CVSS 4.0
2.1 LowCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness
CWE-117
Updated
2026-11-02
EUVDEUVD-2025-25621 2.1

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx.

When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur:

  • Log4cxx is configured to use HTMLLayout.

  • Logger name comes from an untrusted string

  • Logger with compromised name logs a message

  • User opens the generated HTML log file in their browser, leading to potential XSS

Because logger names are generally constant strings, we assess the impact to users as LOW

This issue affects Apache Log4cxx: before 1.5.0.

Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Record
EUVD-2025-25621
CVSS 4.0
2.1 LowCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-7mpr-gcjx-jcmw 2.1

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx. When using HTMLLayout,...

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx.

When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur:

  • Log4cxx is configured to use HTMLLayout.

  • Logger name comes from an untrusted string

  • Logger with compromised name logs a message

  • User opens the generated HTML log file in their browser, leading to potential XSS

Because logger names are generally constant strings, we assess the impact to users as LOW

This issue affects Apache Log4cxx: before 1.5.0.

Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Record
GHSA-7mpr-gcjx-jcmw
CVSS 4.0
2.1 LowCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-117
Updated
2026-11-02
NVD 2.1

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx.

When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur:

  • Log4cxx is configured to use HTMLLayout.

  • Logger name comes from an untrusted string

  • Logger with compromised name logs a message

  • User opens the generated HTML log file in their browser, leading to potential XSS

Because logger names are generally constant strings, we assess the impact to users as LOW

This issue affects Apache Log4cxx: before 1.5.0.

Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Record
CVE-2025-54812
CVSS 4.0
2.1 LowCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-117
Updated
2026-11-02
OSV 2.1

Apache Log4cxx: Improper HTML escaping in HTMLLayout

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx.

When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur:

  • Log4cxx is configured to use HTMLLayout.

  • Logger name comes from an untrusted string

  • Logger with compromised name logs a message

  • User opens the generated HTML log file in their browser, leading to potential XSS

Because logger names are generally constant strings, we assess the impact to users as LOW

This issue affects Apache Log4cxx: before 1.5.0.

Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Record
CVE-2025-54812
CVSS 4.0
2.1 LowCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness
CWE-117
Updated
2026-11-02
OSVDEBIAN-CVE-2025-54812 5.4

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx. When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur: * Log4cxx is configured to use HTMLLayout. * Logger name comes from an untrusted string * Logger with compromised name logs a message * User opens the generated HTML log file in their browser, leading to potential XSS Because logger names are generally constant strings, we assess the impact to users as LOW This issue affects Apache Log4cxx: before 1.5.0. Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Record
DEBIAN-CVE-2025-54812
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Updated
2026-11-02
OSVUBUNTU-CVE-2025-54812 2.1

Improper Output Neutralization for Logs vulnerability in Apache Log4cxx. When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur: * Log4cxx is configured to use HTMLLayout. * Logger name comes from an untrusted string * Logger with compromised name logs a message * User opens the generated HTML log file in their browser, leading to potential XSS Because logger names are generally constant strings, we assess the impact to users as LOW This issue affects Apache Log4cxx: before 1.5.0. Users are recommended to upgrade to version 1.5.0, which fixes the issue.

Record
UBUNTU-CVE-2025-54812
CVSS 4.0
2.1 LowCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
CVSS 3.1
5.4 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Updated
2026-11-02
OSVopenSUSE-SU-2025:15549-1 No score

liblog4cxx-devel-1.5.0-1.1 on GA media

These are all security issues fixed in the liblog4cxx-devel-1.5.0-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2025:15549-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
log4cxx
Debian:12
before 1.0.0-1+deb12u1, plus listed versions
1.0.0-1
1.0.0-1+deb12u1
log4cxx
Debian:13
before 1.4.0-1+deb13u1, plus listed versions
1.4.0-1
1.4.0-1+deb13u1
log4cxx
Debian:14
before 1.4.0-1.1, plus listed versions
1.4.0-1
1.4.0-1.1
log4cxx
Debian:11
From an advisory covering 2 CVEs
before 0.11.0-2+deb11u1, plus listed versions
0.11.0-2
0.11.0-2+deb11u1
log4cxx
Ubuntu:14.04:LTS
All versions, plus listed versions
0.10.0-1.2ubuntu3
None known
log4cxx
Ubuntu:16.04:LTS
All versions, plus listed versions
0.10.0-9ubuntu10.10.0-9ubuntu20.10.0-10ubuntu1
None known
log4cxx
Ubuntu:18.04:LTS
All versions, plus listed versions
0.10.0-12ubuntu10.10.0-13ubuntu10.10.0-13ubuntu2
None known
log4cxx
Ubuntu:20.04:LTS
All versions, plus listed versions
0.10.0-15ubuntu10.10.0-15ubuntu2
None known
log4cxx
Ubuntu:22.04:LTS
All versions, plus listed versions
0.11.0-2ubuntu10.11.0-3ubuntu20.12.1-4
None known
log4cxx
Ubuntu:24.04:LTS
All versions, plus listed versions
1.1.0-11.1.0-1build11.1.0-1build21.1.0-1build3
None known
log4cxx
Ubuntu:25.10
All versions, plus listed versions
1.3.1-11.4.0-1
None known
log4cxx
Ubuntu:26.04:LTS
All versions, plus listed versions
1.4.0-11.5.0-1
None known
log4cxx
openSUSE:Tumbleweed
before 1.5.0-1.1
1.5.0-1.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-54812 is a low vulnerability (CVSS 2.1) in Apache Log4cxx, published August 22, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.24%, the 69th percentile. Fixed in log4cxx 1.0.0-1+deb12u1.

References

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