`CVE-2023-26464` Apache Log4j

Affected software	Apache Log4j
Severity	7.5 High CVSS 3.1 2 scores
Fixed in	`2.0`
Weakness	Deserialization of untrusted data (CWE-502)
Published	10 Mar 2023
Updated	13 Nov 2026

Description

** UNSUPPORTED WHEN ASSIGNED ** When using the Chainsaw or SocketAppender components with Log4j 1.x on JRE less than 1.7, an attacker that manages to cause a logging entry involving a specially-crafted (ie, deeply nested) hashmap or hashtable (depending on which logging component is in use) to be processed could exhaust the available memory in the virtual machine and achieve Denial of Service when the object is deserialized. This issue affects Apache Log4j before 2. Affected users are recommended to update to Log4j 2.x. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

CWE-400 · Uncontrolled resource consumption

Exploitation status

Exploited

Real-world exploitation reported by VulnCheck KEV. CISA has not confirmed it.

CISA KEV not listed
VulnCheck KEV listed Exploitation reported in the wild. 1 citation · earliest 2025-12-08.
CISA Vulnrichment exploitation: none
Indexed PoC none indexed
EPSS 1.9% chance in 30 days

VulnCheck KEV

Exploitation evidence from VulnCheck Known Exploited Vulnerabilities (VulnCheck KEV), used under VulnCheck's community terms. View CVE-2023-26464 in VulnCheck (free account).

Evidence	Source	Detail	Date
Reported exploitation	f5.com	/labs/articles/shellshock-makes-a-comeback-and-rondodox-changes-tactics	2025-12-08

Evidence

Source

Detail

Date

Reported exploitation

f5.com

/labs/articles/shellshock-makes-a-comeback-and-rondodox-changes-tactics

2025-12-08

Waratek protection

Protected by Waratek

Waratek has a rule that blocks attacks on this vulnerability.

Protection full
Action available patch rule
Review human ARMR file
Record active

Decided by	An ARMR patch file on disk for this CVE
Finding	CVE is covered by a multi-CVE ARMR patch rule

Decided by

An ARMR patch file on disk for this CVE

Finding

CVE is covered by a multi-CVE ARMR patch rule

ARMR rule files

1 file

The rule files Waratek ships for this CVE. Some CVEs need more than one, for example one per affected library or one per ARMR version.

CVE-2023-26464.armr patch rule, ARMR 2.6 added 2021-12-15 updated 2026-03-04

Waratek research note

written 2026-11-13

Written by a Waratek engineer who reviewed this CVE. Their decision sets the status above, ahead of every automated rule except a withdrawal.

Comments

Covered by patch for CVE-2021-45046

How to mitigate CVE-2023-26464

Upgrade Apache Log4j to 2.0 or later. Until you can, Waratek RASP blocks exploitation with a rule written for this CVE. It runs inside the Java application, with no code changes.

Waratek RASP Runtime protection for Java applications

CVSS

7.5 HIGH v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

Version Score Band Vector Assigner Type

CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H NVD Primary published

CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CISA-ADP Secondary

Version	Score	Band	Vector	Assigner	Type
CVSS 3.1	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`	NVD	Primary	published
CVSS 3.1	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`	CISA-ADP	Secondary

Affected software and releases

Oracle advisories

Advisory	Type	Quarter	Products Oracle names in its risk matrix
Oracle Critical Security Patch Update August 2026 ↗	CSPU	2026-Q3	Oracle Hyperion / Installation and Configuration (Apache Log4j) (11.2.25.0.000)
Oracle Critical Patch Update April 2026 ↗	CPU	2026-Q2	Oracle Siebel CRM / Server Infrastructure (Apache Log4j) (17.0-25.11)
Oracle Critical Patch Update April 2025 ↗	CPU	2025-Q2	Oracle Food and Beverage Applications / Installation (Apache Log4j) (9.1.34-9.1.36) Oracle Fusion Middleware / Generic (Apache Log4j) (12.2.1.4.0)
Oracle Critical Patch Update October 2024 ↗	CPU	2024-Q4	Oracle Analytics / BI Application Archive (Apache Log4j) (7.0.0.0.0)

Advisory

Type

Quarter

Products Oracle names in its risk matrix

Oracle Critical Security Patch Update August 2026 ↗

CSPU

2026-Q3

Oracle Hyperion / Installation and Configuration (Apache Log4j) (11.2.25.0.000)

Oracle Critical Patch Update April 2026 ↗

CPU

2026-Q2

Oracle Siebel CRM / Server Infrastructure (Apache Log4j) (17.0-25.11)

Oracle Critical Patch Update April 2025 ↗

CPU

2025-Q2

Oracle Food and Beverage Applications / Installation (Apache Log4j) (9.1.34-9.1.36)
Oracle Fusion Middleware / Generic (Apache Log4j) (12.2.1.4.0)

Oracle Critical Patch Update October 2024 ↗

CPU

2024-Q4

Oracle Analytics / BI Application Archive (Apache Log4j) (7.0.0.0.0)

Oracle components and versions

Family	Component	Versions, as Oracle lists them	Read as
Oracle Analytics	BI Application Archive (Apache Log4j)	7.0.0.0.0	7.0.0.0.0
Oracle Food and Beverage Applications	Installation (Apache Log4j)	9.1.34-9.1.36
Oracle Fusion Middleware	Generic (Apache Log4j)	12.2.1.4.0	12.2.1.4.0
Oracle Hyperion	Installation and Configuration (Apache Log4j)	11.2.25.0.000	11.2.25.0.0
Oracle Siebel CRM	Server Infrastructure (Apache Log4j)	17.0-25.11

Maven packages

Affected and fixed versions, from OSV.dev

Package Introduced Fixed Last affected

org.apache.logging.log4j:log4j-core 1.0.4 2.0 unbounded

log4j:log4j 1.0.4 2.0 unbounded

Package	Introduced	Fixed	Last affected
`org.apache.logging.log4j:log4j-core`	1.0.4	`2.0`	unbounded
`log4j:log4j`	1.0.4	`2.0`	unbounded

Products and versions

3 products, 3 version entries

Source	Vendor	Product	Scheme	Affected versions
nvd	apache	log4j	generic	≥ 1.0.4 and ＜ 2.0
osv	log4j	log4j	generic	≥ 1.0.4 and ＜ 2.0
osv	org.apache.logging.log4j	log4j-core	generic	≥ 1.0.4 and ＜ 2.0

Source

Vendor

Product

Scheme

Affected versions

nvd

apache

log4j

generic

≥ 1.0.4 and ＜ 2.0

osv

log4j

generic

≥ 1.0.4 and ＜ 2.0

osv

org.apache.logging.log4j

log4j-core

generic

≥ 1.0.4 and ＜ 2.0

References

URL	Tags
https://github.com/apache/logging-log4j2	PACKAGE
https://lists.apache.org/thread/wkx6grrcjkh86crr49p4blc1v1nflj3t	WEB
https://security.netapp.com/advisory/ntap-20230505-0008	WEB
https://security.netapp.com/advisory/ntap-20230505-0008/

URL

Timeline

ARMR remediation created	2021-12-15	Earliest commit adding this CVE's ARMR patch or security rule.
Published	2023-03-10	By the CVE Program.
VulnCheck KEV: earliest evidence	2025-12-08	Date of the oldest evidence of exploitation in VulnCheck KEV's record. VulnCheck does not publish the date it listed the CVE.
ARMR remediation last updated	2026-03-04	Most recent commit touching this CVE's ARMR patch or security rule.
NVD record modified	2026-06-17	NVD's own last-modified date for this record.
Classification created	2026-11-13	First commit adding this CVE's research note.
Last VRT activity	2026-11-13	Most recent commit touching this CVE's classification, patch or rule file.

ARMR remediation created

2021-12-15

Earliest commit adding this CVE's ARMR patch or security rule.

Published

2023-03-10

By the CVE Program.

VulnCheck KEV: earliest evidence

2025-12-08

Date of the oldest evidence of exploitation in VulnCheck KEV's record. VulnCheck does not publish the date it listed the CVE.

ARMR remediation last updated

2026-03-04

Most recent commit touching this CVE's ARMR patch or security rule.

NVD record modified

2026-06-17

NVD's own last-modified date for this record.

Classification created

2026-11-13

First commit adding this CVE's research note.

Last VRT activity

2026-11-13

Most recent commit touching this CVE's classification, patch or rule file.

How VRT decided (2 of 24 rules ran)

2 of 24 rules ran. The rest didn't run because an earlier rule had already settled the CVE.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? the first rule that matches decides

1 rejected no match CVE Program withdrawal of this identifier

scope: Is it a vulnerability Waratek protects? the first rule that matches decides

2 armr-patch-file decided it matched Protected by Waratek Covered by ARMR patch: CVE-2023-26464.armr

3 armr-secure-rule-file not reached An ARMR security-rule template on disk for this CVE

4 manual-classification not reached A researcher's recorded decision for this specific CVE

5 manual classification not reached Manual classification of this CVE in the legacy dataset

6 non-java-upstream not reached A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component not reached The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the JInitiator browser plug-in, the native WebLogic proxy plug-in, or a native part of Oracle Application Server or Collaboration Suite (HTTP Server, Web Cache, Internet Directory, mail and calendar servers). Oracle gives these no CPE of their own and names them only in the description.

8 java-client-side not reached Oracle's own risk-matrix note saying the CVE is reached only through untrusted code in the Java sandbox (applets, Web Start) or only through a client installation of Java, so a server running its own trusted code is not exposed

9 osv-maven not reached An OSV.dev record of this CVE affecting a package published to Maven Central. When every such package is one business applications do not use (Minecraft mods and launchers, Fastjson) and no tracked product is named by CPE, it settles the CVE as Outside Waratek scope instead

10 cna-maven-package not reached An affected Maven artifact named by the CNA itself

11 known-cpe-product not reached An NVD CPE naming a product ARMR tracks

12 cna-cpe-product not reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

13 oracle-advisory-family not reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

14 cna-named-product not reached A tracked product named in words by the CVE's own CNA, on a record with no CPE yet. Apache and Eclipse publish these on advisory day, before NVD adds CPE data.

15 non-deployable-product not reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

16 unmatched-product not reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? every rule runs

17 patch-hint not reached A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug

18 open-source-maven not reached The affected package being open source on Maven, so the fix can be read

19 poc-derivable not reached An indexed exploit clearing the evidence bar to reverse-engineer, where there is no source to read

20 no-exploit not reached Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read

21 secure-rule-match not reached A vulnerability class already blocked by an ARMR security rule

22 exploited-no-fix-or-poc not reached Somebody exploiting this CVE (a CISA or VulnCheck KEV listing, or a CISA verdict of active exploitation), with no fix, source code or PoC to build a rule from

23 below-action-threshold not reached Medium or Low severity, no CISA or VulnCheck KEV listing, no PoC clearing the evidence bar, no CISA verdict, no Oracle advisory

24 no-exploit-published not reached Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all

NVD ↗ · CVE.org ↗