Local-service access via nondecimal IPv4 parsing
Published Oct 7, 2021 · Updated Aug 3, 2024
SSRF in Concrete CMS before 8.5.5 allows remote authenticated users to reach local services through alternate IPv4 notation. The URL destination validator passes nondecimal IPv4 literals without canonicalizing them before its localhost check, while the HTTP client resolves them to loopback. Exploitation requires high-privilege access to the URL-fetching feature, and resulting access is limited to services reachable from the CMS host.
Summary
What happened
SSRF in Concrete CMS before 8.5.5 allows remote authenticated users to reach local services through alternate IPv4 notation. The URL destination validator passes nondecimal IPv4 literals without canonicalizing them before its localhost check, while the HTTP client resolves them to loopback. Exploitation requires high-privilege access to the URL-fetching feature, and resulting access is limited to services reachable from the CMS host.
The record
- CVE
- CVE-2021-22958
- Published
- Oct 7, 2021
- Updated
- Aug 3, 2024
- Vendor
- Concrete CMS
- Product
- Concrete CMS
- Classifications
- CWE-918, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 7, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 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.
- Affected versionversion=Fixed in 8.5.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
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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