CVE-2026-55431Network attack vector

Account impersonation via external app token substitution

Published Jul 8, 2026 · Updated Jul 8, 2026

Credential exposure in affected Coder CLI releases allows remote authenticated users to impersonate victims through external app URLs. The coder open app path replaces a $SESSION_TOKEN placeholder in an attacker-controlled workspace-app URL with the victim's live token before passing the URL to the operating system. Exploitation requires a user to invoke the command for a malicious workspace app; the disclosed token grants full account access for its lifetime.

CVSS severity7.7
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Credential exposure in affected Coder CLI releases allows remote authenticated users to impersonate victims through external app URLs. The coder open app path replaces a $SESSION_TOKEN placeholder in an attacker-controlled workspace-app URL with the victim's live token before passing the URL to the operating system. Exploitation requires a user to invoke the command for a malicious workspace app; the disclosed token grants full account access for its lifetime.

The record

CVE
CVE-2026-55431
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
Coder
Product
Coder
Classifications
CWE-522, CWE-601, T1528
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 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=< 2.29.17
  2. Affected versionversion=>= 2.30.0, < 2.32.7
  3. Affected versionversion=>= 2.33.0, < 2.33.8
  4. Affected versionversion=>= 2.34.0, < 2.34.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Coder · Coderversion=< 2.29.17; version=>= 2.30.0, < 2.32.7; version=>= 2.33.0, < 2.33.8; version=>= 2.34.0, < 2.34.2

Published CVSS scores

7.7GitHubCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials
CWE-601URL Redirection to Untrusted Site ('Open Redirect')
T1528Steal Application Access Token

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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