CVE-2021-41088Network attack vector

Code execution via origin-unchecked web endpoint

Published Sep 23, 2021 · Updated Aug 4, 2024

Origin validation error in the Elvish web UI before 0.14.0 allows remote attackers to execute arbitrary code through localhost requests. The /execute handler reads the entire HTTP request body as Elvish source and passes it directly to the evaluator without validating its origin. Exploitation requires the experimental web backend to be running and a local user to visit an attacker-controlled or compromised website; executed code runs with that user's privileges.

CVSS severity8.8
High
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in the Elvish web UI before 0.14.0 allows remote attackers to execute arbitrary code through localhost requests. The /execute handler reads the entire HTTP request body as Elvish source and passes it directly to the evaluator without validating its origin. Exploitation requires the experimental web backend to be running and a local user to visit an attacker-controlled or compromised website; executed code runs with that user's privileges.

The record

CVE
CVE-2021-41088
Published
Sep 23, 2021
Updated
Aug 4, 2024
Vendor
Elves
Product
Elvish
Classifications
CWE-346, CWE-668, T1203, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=< 0.14.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Elves · Elvishversion=< 0.14.0

Published CVSS scores

9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.0GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/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-346Origin Validation Error
CWE-668Exposure of Resource to Wrong Sphere
T1203Exploitation for Client Execution
T1204.001User Execution: Malicious Link

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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