CVE-2026-79786Public exploitNetwork attack vectorHinoki check available

MCP session hijack via unvalidated OAuth redirect

Published Aug 25, 2026 · Updated Aug 28, 2026

Open redirect in Coroot 1.20.2 through 1.24.5 allows remote attackers to steal MCP access tokens through crafted OAuth authorization links. The unauthenticated /oauth/register handler accepts any URL that url.Parse considers syntactically valid and embeds it in a signed client identifier without restricting its scheme or host. A signed-in user must approve the attacker's consent request before Coroot sends the authorization code to the registered host, where it can be exchanged for an MCP access token.

CVSS severity7.0
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Open redirect in Coroot 1.20.2 through 1.24.5 allows remote attackers to steal MCP access tokens through crafted OAuth authorization links. The unauthenticated /oauth/register handler accepts any URL that url.Parse considers syntactically valid and embeds it in a signed client identifier without restricting its scheme or host. A signed-in user must approve the attacker's consent request before Coroot sends the authorization code to the registered host, where it can be exchanged for an MCP access token.

The record

CVE
CVE-2026-79786
Published
Aug 25, 2026
Updated
Aug 28, 2026
Vendor
Coroot
Product
Coroot
Classifications
CWE-601, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 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=1.20.2 <=1.24.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Coroot · Corootversion=1.20.2 <=1.24.5

Published CVSS scores

7.1Positive TechnologiesCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
7.0VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

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 exploitPublished

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
T1528Steal Application Access Token

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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