Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.
CWE-298 Variant Draft
Improper Validation of Certificate Expiration
This vulnerability occurs when an application fails to properly check if a digital certificate has expired, potentially trusting certificates that are no longer valid due to their age.
Definition
What is CWE-298?
This vulnerability occurs when an application fails to properly check if a digital certificate has expired, potentially trusting certificates that are no longer valid due to their age.
Digital certificates have built-in expiration dates for security reasons, similar to how a driver's license needs renewal. When your application doesn't verify this expiration, it might continue to trust certificates that have been abandoned or revoked, creating a false sense of security in your authentication or encryption processes.
This oversight completely undermines the certificate's purpose, as you cannot verify whether the certificate holder still has legitimate access. To prevent this, always implement proper date validation against the certificate's 'valid from' and 'valid to' timestamps during every verification routine.
Real-world impact
Real-world CVEs caused by CWE-298
No public CVE references are linked to this CWE in MITRE's catalog yet.
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
Vulnerable C
The following OpenSSL code ensures that there is a certificate and allows the use of expired certificates.
if (cert = SSL_get_peer(certificate(ssl)) {
foo=SSL_get_verify_result(ssl);
if ((X509_V_OK==foo) || (X509_V_ERR_CERT_HAS_EXPIRED==foo))
```
//do stuff* Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-298
- Architecture and Design Check for expired certificates and provide the user with adequate information about the nature of the problem and how to proceed.
- Implementation If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the expiration.
Detection signals
How to detect CWE-298
Run dynamic application security testing against the live endpoint.
Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.
Code review: flag any new code that handles input from this surface without using the validated framework helpers.
Plexicus auto-detects CWE-298 and opens a fix PR in under 60 seconds.
Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.
Frequently asked questions What is CWE-298?
How serious is CWE-298?
What languages or platforms are affected by CWE-298?
How can I prevent CWE-298?
How does Plexicus detect and fix CWE-298?
Where can I learn more about CWE-298?
Frequently asked questions
What is CWE-298?
This vulnerability occurs when an application fails to properly check if a digital certificate has expired, potentially trusting certificates that are no longer valid due to their age.
How serious is CWE-298?
MITRE rates the likelihood of exploit as Low — exploitation is uncommon, but the weakness should still be fixed when discovered.
What languages or platforms are affected by CWE-298?
MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.
How can I prevent CWE-298?
Check for expired certificates and provide the user with adequate information about the nature of the problem and how to proceed. If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the expiration.
How does Plexicus detect and fix CWE-298?
Plexicus's SAST engine matches the data-flow signature for CWE-298 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-298?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/298.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-298
CWE-295 Parent
Improper Certificate Validation
This vulnerability occurs when an application fails to properly verify the authenticity of a digital certificate, or performs the…
CWE-296 Sibling
Improper Following of a Certificate's Chain of Trust
This vulnerability occurs when software fails to properly validate the entire certificate chain back to a trusted root authority. This…
CWE-297 Sibling
Improper Validation of Certificate with Host Mismatch
This vulnerability occurs when an application accepts a valid SSL/TLS certificate without properly verifying that it actually belongs to…
CWE-299 Sibling
Improper Check for Certificate Revocation
This vulnerability occurs when an application fails to properly verify whether a security certificate has been revoked, potentially…
CWE-599 Sibling
Missing Validation of OpenSSL Certificate
This vulnerability occurs when an application uses OpenSSL but fails to properly verify server certificates by not calling…
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