CVE-2026-43982Network attack vector

Arbitrary file write via unchecked savein path

Published May 26, 2026 · Updated May 26, 2026

Path traversal in Algernon before 1.17.6 allows remote attackers to write uploaded files outside the web root through crafted savein directories. uploadedFileSaveIn() in lua/upload/upload.go joins the caller-supplied directory with filepath.Join() but never verifies that the result remains beneath the web root. Exploitation requires an upload-enabled Lua application without its own directory safeguards; writable destinations follow the Algernon service account permissions.

CVSS severity8.7
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

Path traversal in Algernon before 1.17.6 allows remote attackers to write uploaded files outside the web root through crafted savein directories. uploadedFileSaveIn() in lua/upload/upload.go joins the caller-supplied directory with filepath.Join() but never verifies that the result remains beneath the web root. Exploitation requires an upload-enabled Lua application without its own directory safeguards; writable destinations follow the Algernon service account permissions.

The record

CVE
CVE-2026-43982
Published
May 26, 2026
Updated
May 26, 2026
Vendor
xyproto
Product
Algernon
Classifications
CWE-22, T1105
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2026CVE publishedPublication date reported by the CVE source.
  2. May 26, 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=< 1.17.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

xyproto · Algernonversion=< 1.17.6

Published CVSS scores

8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1105Ingress Tool Transfer

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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