CVE-2026-73255Public exploitNetwork attack vector

Arbitrary file read via unsanitized SSI includes

Published Aug 20, 2026 · Updated Aug 25, 2026

Path traversal in Cesanta Mongoose before 7.22 allows remote authenticated users to read process-accessible files through SSI includes. The mg_ssi() function in src/ssi.c concatenates an untrusted file or virtual directive argument into a filesystem path without mg_path_is_sane() validation. Exploitation requires MG_ENABLE_SSI, a configured ssi_pattern, and attacker control of an SSI-enabled file; disclosure is limited to files readable by the Mongoose process.

CVSS severity6.5
Medium
EPSS probability0.59%
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 Cesanta Mongoose before 7.22 allows remote authenticated users to read process-accessible files through SSI includes. The mg_ssi() function in src/ssi.c concatenates an untrusted file or virtual directive argument into a filesystem path without mg_path_is_sane() validation. Exploitation requires MG_ENABLE_SSI, a configured ssi_pattern, and attacker control of an SSI-enabled file; disclosure is limited to files readable by the Mongoose process.

The record

CVE
CVE-2026-73255
Published
Aug 20, 2026
Updated
Aug 25, 2026
Vendor
Cesanta
Product
Mongoose
Classifications
CWE-22, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=< 7.22

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cesanta · Mongooseversion=< 7.22

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System

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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