CVE-2026-55685Network attack vector

Service slowdown via repeated route-pattern compilation

Published Jul 27, 2026 · Updated Jul 27, 2026

Algorithmic-complexity DoS in Shopify React Router 7.0.0 through 7.17.0 allows remote attackers to slow Framework Mode servers. The __manifest handler repeatedly compiles route-path regular expressions while matching attacker-controlled requested paths instead of reusing precomputed matchers. Only Framework Mode applications expose the affected manifest path; Declarative and Data Mode applications are unaffected, and the observed consequence is degraded response time rather than data access or modification.

CVSS severity8.7
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic-complexity DoS in Shopify React Router 7.0.0 through 7.17.0 allows remote attackers to slow Framework Mode servers. The __manifest handler repeatedly compiles route-path regular expressions while matching attacker-controlled requested paths instead of reusing precomputed matchers. Only Framework Mode applications expose the affected manifest path; Declarative and Data Mode applications are unaffected, and the observed consequence is degraded response time rather than data access or modification.

The record

CVE
CVE-2026-55685
Published
Jul 27, 2026
Updated
Jul 27, 2026
Vendor
Shopify
Product
React Router
Classifications
CWE-400, CWE-407, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 27, 2026Record 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=>= 7.0.0, < 7.18.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shopify · React Routerversion=>= 7.0.0, < 7.18.0

Published CVSS scores

8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5Red HatCVSS: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-400Uncontrolled Resource Consumption
CWE-407Inefficient Algorithmic Complexity
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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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