CVE-2026-13221
9.1 · CRITICALOverview
CVE-2026-13221 is a critical-severity vulnerability affecting perl perl. It was published on July 13, 2026 and has a CVSS 3.1 base score of 9.1 (CRITICAL).
This vulnerability has a CVSS 3.1 base score of 9.1, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk.
When such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie's match decision table is truncated with no warning or error.
A pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong.
Remediation
Check the references section for vendor advisories and patches from perl. Update perl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| perl | perl | 0 | Affected |
Frequently Asked Questions
What is CVE-2026-13221?
CVE-2026-13221 is a critical-severity vulnerability affecting perl perl. It was published on July 13, 2026 and has a CVSS 3.1 base score of 9.1 (CRITICAL).
How severe is CVE-2026-13221?
This vulnerability has a CVSS 3.1 base score of 9.1, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-13221?
Check the references section for vendor advisories and patches from perl. Update perl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-13221?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-13221 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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