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» CVE-2021-26642
When uploading an image file to a bulletin board developed with XpressEngine, a vulnerability in which an arbitrary file can be uploaded due to insufficient verification of the file. A remote attacker can use this vulnerability to execute arbitrary code on the server where the bulletin board is running.
NVD Status： Modified ，CVE State: published
Threat Intelligence & Risk Assessment for CVE-2021-26642
Conclusion & alert: CVE-2021-26642 is rated Moderate Risk (55/100) : CVSS High severity, with medium exploitation likelihood (EPSS 1.16%).Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
Exploit prediction scoring system (EPSS) score for CVE-2021-26642
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
#
Date
Old EPSS score
New EPSS score
Delta (New - Old)
1
2026-06-15
3.39%
1.16%
-2.23%
2
2026-03-17
3.28%
3.39%
+0.11%
3
2026-01-21
—
3.28%
—
Full EPSS history
(19 records total)
Common vulnerability scoring system (CVSS) metrics for CVE-2021-26642
CVSS metrics for this CVE.
Base score
Version
Severity
Vector
Exploitability
Impact
Score source
8.8
3.1
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
2.8
5.9
[email protected]
9.8
3.1
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9
5.9
[email protected]
Weakness enumeration for CVE-2021-26642
GitHub Security Advisory for CVE-2021-26642
GHSA-8r5j-22j5-w4cm · Severity: critical · Ecosystem: composer
— XpressEngine vulnerable to Unrestricted Upload of File with Dangerous Type
Affected software / configurations for CVE-2021-26642
References for CVE-2021-26642
cvelogic
Threat Intelligence