CVE-2025-47908Public exploitNetwork attack vector

Service degradation via comma-heavy preflight headers

Published Aug 6, 2025 · Updated Aug 7, 2025

Resource exhaustion in rs cors 1.9.0 through 1.10.1 allows remote attackers to degrade service via crafted CORS preflight requests. The handlePreflight path splits comma-delimited ACRH values into slices, canonicalizes empty tokens, and repeatedly scans allowed headers. Any unauthenticated client that can reach a server using the middleware can force excessive heap allocation and CPU work, reducing availability without changing data.

CVSS severity7.5
High
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in rs cors 1.9.0 through 1.10.1 allows remote attackers to degrade service via crafted CORS preflight requests. The handlePreflight path splits comma-delimited ACRH values into slices, canonicalizes empty tokens, and repeatedly scans allowed headers. Any unauthenticated client that can reach a server using the middleware can force excessive heap allocation and CPU work, reducing availability without changing data.

The record

CVE
CVE-2025-47908
Published
Aug 6, 2025
Updated
Aug 7, 2025
Vendor
rs
Product
cors
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 6, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 7, 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=1.9.0 <1.11.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

rs · corsversion=1.9.0 <1.11.0

Published CVSS scores

7.5CVE ProgramCVSS: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 exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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