CVE-2021-4456
Essential information
- Published
- 27/02/2026 01:16
- Modified
- 27/02/2026 17:16
- Author
- —
- Creator
- —
- CVSS
- 6.5 MEDIUM (v3.1)
- CISA KEV
- No
- CWE
- —
- CVSS vector
-
—
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N—
CVSS metrics
- Access vector
- —
- Access complexity
- —
- Authentication
- —
- Confidentiality impact
- —
- Integrity impact
- —
- Availability impact
- —
- Exploitability
- —
- Remediation level
- —
- Report confidence
- —
- Temporal score
- —
- Attack vector
- NETWORK
- Attack complexity
- LOW
- Privileges required
- NONE
- User interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality impact
- LOW
- Integrity impact
- LOW
- Availability impact
- NONE
- Exploit code maturity
- —
- Remediation level
- —
- Report confidence
- —
- Temporal score
- —
- Attack vector
- —
- Attack complexity
- —
- Attack requirements
- —
- Privileges required
- —
- User interaction
- —
- Confidentiality (V)
- —
- Confidentiality (S)
- —
- Integrity (V)
- —
- Integrity (S)
- —
- Availability (V)
- —
- Availability (S)
- —
- Exploit maturity
- —
Description
Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.
The functions `addr2cidr` and `cidrlookup` may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.
The documentation advises validating untrusted CIDR strings with the `cidrvalidate` function. However, this mitigation is optional and not enforced by default. In practice, users may call `addr2cidr` or `cidrlookup` with untrusted input and without validation, incorrectly assuming that this is safe.
NVD status
- Status
- Awaiting Analysis — CVE has been recently published to the CVE List and has been received by the NVD.
- Source
- 9b29abf9-4ab0-4765-b253-1875cd9b441e
- NVD
- View on NVD
Affected products (CPE)
| Product | CPE |
|---|---|
| perl / net | cpe:2.3:a:perl:net::cidr:<0.24:*:*:*:*:*:* |