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Vulnerability details: VCID-6khs-z7j6-t3d5
Vulnerability ID VCID-6khs-z7j6-t3d5
Aliases CVE-2026-21857
GHSA-824x-88xg-cwrv
Summary REDAXO is a PHP-based content management system. Prior to version 5.20.2, authenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality. The Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories. An attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive. Version 5.20.2 fixes this issue.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-24 Path Traversal: '../filedir'
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00035 https://api.first.org/data/v1/epss?cve=CVE-2026-21857
epss 0.00035 https://api.first.org/data/v1/epss?cve=CVE-2026-21857
epss 0.00035 https://api.first.org/data/v1/epss?cve=CVE-2026-21857
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-824x-88xg-cwrv
cvssv4 8.3 https://github.com/redaxo/redaxo
generic_textual HIGH https://github.com/redaxo/redaxo
cvssv4 8.3 https://github.com/redaxo/redaxo/releases/tag/5.20.2
generic_textual HIGH https://github.com/redaxo/redaxo/releases/tag/5.20.2
ssvc Track https://github.com/redaxo/redaxo/releases/tag/5.20.2
cvssv3.1_qr HIGH https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
cvssv4 8.3 https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
generic_textual HIGH https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
ssvc Track https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
cvssv4 8.3 https://nvd.nist.gov/vuln/detail/CVE-2026-21857
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2026-21857
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2026-21857
5.20.2 https://github.com/redaxo/redaxo/releases/tag/5.20.2
CVE-2026-21857 https://nvd.nist.gov/vuln/detail/CVE-2026-21857
GHSA-824x-88xg-cwrv https://github.com/advisories/GHSA-824x-88xg-cwrv
GHSA-824x-88xg-cwrv https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
No exploits are available.
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N Found at https://github.com/redaxo/redaxo
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N Found at https://github.com/redaxo/redaxo/releases/tag/5.20.2
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

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none

passive

active

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Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-01-08T15:09:21Z/ Found at https://github.com/redaxo/redaxo/releases/tag/5.20.2
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N Found at https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

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Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-01-08T15:09:21Z/ Found at https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N Found at https://nvd.nist.gov/vuln/detail/CVE-2026-21857
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

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low

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none
Exploit Prediction Scoring System (EPSS)
Percentile 0.10775
EPSS Score 0.00035
Published At June 11, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-11T16:47:08.521560+00:00 Vulnrichment Import https://github.com/cisagov/vulnrichment/blob/develop/2026/21xxx/CVE-2026-21857.json 38.6.0