CVE-2022-0957Network attack vector

Stored XSS via allowed .m3u8a attachment upload

Published Mar 15, 2022 · Updated Aug 2, 2024

Stored XSS in ShowDoc before 2.10.4 allows remote authenticated users to run script in another user's browser via a file upload. AttachmentModel::isAllowedFilename treats the .m3u8a suffix as an allowed attachment type, so attacker-controlled active content is stored and served. An account capable of uploading an attachment and a user who opens it are required; the script executes in the viewer's ShowDoc origin.

CVSS severity5.4
Medium
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in ShowDoc before 2.10.4 allows remote authenticated users to run script in another user's browser via a file upload. AttachmentModel::isAllowedFilename treats the .m3u8a suffix as an allowed attachment type, so attacker-controlled active content is stored and served. An account capable of uploading an attachment and a user who opens it are required; the script executes in the viewer's ShowDoc origin.

The record

CVE
CVE-2022-0957
Published
Mar 15, 2022
Updated
Aug 2, 2024
Vendor
ShowDoc
Product
ShowDoc
Classifications
CWE-79, CAPEC-592, CAPEC-209, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 15, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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=unspecified <2.10.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ShowDoc · ShowDocversion=unspecified <2.10.4

Published CVSS scores

3.5NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
7.6huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:L

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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-592Stored XSS
CAPEC-209XSS Using MIME Type Mismatch
T1189Drive-by Compromise

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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