CVE-2023-26464Network attack vector

Service interruption via nested collection deserialization

Published Mar 10, 2023 · Updated Feb 13, 2025

Deserialization in Apache Log4j before 2.0 allows remote attackers to exhaust JVM memory through crafted logging objects. Chainsaw or SocketAppender deserializes a deeply nested HashMap or Hashtable without bounding the memory consumed during reconstruction. Reachability requires one of those components on a JRE before 1.7 and attacker influence over a processed logging entry; the result is service interruption.

CVSS severity7.5
High
EPSS probability1.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in Apache Log4j before 2.0 allows remote attackers to exhaust JVM memory through crafted logging objects. Chainsaw or SocketAppender deserializes a deeply nested HashMap or Hashtable without bounding the memory consumed during reconstruction. Reachability requires one of those components on a JRE before 1.7 and attacker influence over a processed logging entry; the result is service interruption.

The record

CVE
CVE-2023-26464
Published
Mar 10, 2023
Updated
Feb 13, 2025
Vendor
The Apache Software Foundation
Product
Apache Log4j
Classifications
CWE-502, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.4 <2
  2. Affected versionversion=1.0.4 <2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Log4jversion=1.0.4 <2; version=1.0.4 <2.0

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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