CVE-2023-20861Network attack vector

Application denial of service via repeated regex compilation

Published Mar 23, 2023 · Updated Feb 25, 2025

Spring Framework affected releases allow remote attackers to interrupt applications by submitting a crafted SpEL expression. InternalSpelExpressionParser gives each matches node a separate regular-expression cache, so one expression repeatedly compiles the same pattern and exhausts resources. The application must evaluate attacker-controlled SpEL; affected lines are 6.0.0 through 6.0.6, 5.3.0 through 5.3.25, and 5.2.22.RELEASE and earlier.

CVSS severity6.5
Medium
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Spring Framework affected releases allow remote attackers to interrupt applications by submitting a crafted SpEL expression. InternalSpelExpressionParser gives each matches node a separate regular-expression cache, so one expression repeatedly compiles the same pattern and exhausts resources. The application must evaluate attacker-controlled SpEL; affected lines are 6.0.0 through 6.0.6, 5.3.0 through 5.3.25, and 5.2.22.RELEASE and earlier.

The record

CVE
CVE-2023-20861
Published
Mar 23, 2023
Updated
Feb 25, 2025
Vendor
Spring
Product
Spring Framework
Classifications
CWE-917, CWE-400, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 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=Spring Framework (6.0.0 to 6.0.6, 5.3.0 to 5.3.25, 5.2.0.RELEASE to 5.2.22.RELEASE, Older unsupported versions are also affected)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Spring · Spring Frameworkversion=Spring Framework (6.0.0 to 6.0.6, 5.3.0 to 5.3.25, 5.2.0.RELEASE to 5.2.22.RELEASE, Older unsupported versions are also affected)

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-917Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
CWE-400Uncontrolled Resource Consumption
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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