Is CVE-2026-34479 in the CISA KEV catalog?

No. CVE-2026-34479 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34479?

CVE-2026-34479 has a CVSS v3 base score of 7.5 (Low).

What is the EPSS score for CVE-2026-34479?

CVE-2026-34479 has an EPSS score of 0.53% (41th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-34479

Q: How do I fix CVE-2026-34479?

Upgrade registry.redhat.io/offline-knowledge on rhel 8 to portal/rhokp-rhel9@sha256:b26253f0a6c6b9e8c8458ecb07e79e9f87ff313491fffc31e342e32bce0a2b3e_arm64 or later. Fixes are available for 2 affected products.

LOW

7.5

CVSS v3

NVD

Description

The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records. Two groups of users are affected: * Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file. * Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class. Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue. Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.

CWE-116

How to fix

Remediation Available

registry.redhat.io/offline-knowledgeRed Hat / RHEL

Fixed in:portal/rhokp-rhel9@sha256:b26253f0a6c6b9e8c8458ecb07e79e9f87ff313491fffc31e342e32bce0a2b3e_arm64RHSA-2026:21773

Fixed in:portal/rhokp-rhel9@sha256:ec8b14b7a170b689a19cee7820888e81ddc3affc2faada6cc6139644f328bd36_amd64RHSA-2026:21773

registry.redhat.io/offline-knowledgeRocky

Fixed in:portal/rhokp-rhel9@sha256:ec8b14b7a170b689a19cee7820888e81ddc3affc2faada6cc6139644f328bd36_amd64RHSA-2026:21773

Fixed in:portal/rhokp-rhel9@sha256:b26253f0a6c6b9e8c8458ecb07e79e9f87ff313491fffc31e342e32bce0a2b3e_arm64RHSA-2026:21773

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploit Intelligence

0.53%probability of exploitation in 30 days

41stpercentile

Moderate risk: more likely to be exploited than 41% of all known CVEs.

References

Patch1

github.com

Vendor Advisory2

Mitigation1

logging.apache.org

Mailing List2

Related Vulnerabilities

Other CWE-116 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-38475	Critical	9.1	100%	KEV	Fix
CVE-2022-36446	Critical	9.8	96%	-	Fix
CVE-2021-31806	Medium	6.5	96%	-	Fix
CVE-2022-30781	High	7.5	88%	-	Fix
CVE-2022-36099	Critical	9.9	76%	-	Fix
CVE-2022-36100	Critical	9.9	74%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-06.