Unauthenticated memory exhaustion via forwarded-header regex
Published Feb 12, 2025 · Updated Feb 12, 2025
Regular expression denial of service in Koa allows remote attackers to exhaust memory by sending crafted forwarded-host or protocol headers. With proxy mode enabled, request.js splits X-Forwarded-Host and X-Forwarded-Proto values using a whitespace-heavy regular expression with excessive worst-case complexity. Unauthenticated network requests can consume application memory and interrupt the Koa service, while deployments without proxy mode do not reach these header getters.
Summary
What happened
Regular expression denial of service in Koa allows remote attackers to exhaust memory by sending crafted forwarded-host or protocol headers. With proxy mode enabled, request.js splits X-Forwarded-Host and X-Forwarded-Proto values using a whitespace-heavy regular expression with excessive worst-case complexity. Unauthenticated network requests can consume application memory and interrupt the Koa service, while deployments without proxy mode do not reach these header getters.
The record
- CVE
- CVE-2025-25200
- Published
- Feb 12, 2025
- Updated
- Feb 12, 2025
- Vendor
- Koa.js
- Product
- Koa
- Classifications
- CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 12, 2025CVE publishedPublication date reported by the CVE source.
- Feb 12, 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.
- Affected versionversion=< 0.21.2
- Affected versionversion=>= 1.0.0, < 1.7.1
- Affected versionversion=>= 2.0.0-alpha.1, < 2.15.4
- Affected versionversion=>= 3.0.0-alpha.0, < < 3.0.0-alpha.3
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
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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