Overview
CVE-2026-109618 has been added to the CISA Known Exploited Vulnerabilities catalog. Published on October 21, 2026. Threat actors are actively exploiting this vulnerability in real-world attacks.
PHP uses longjmp() for out-of-memory (OOM) errors to exit the current context and abort handling of the request.
Threat Intelligence
| Metric | Value |
|---|---|
| CVE ID | CVE-2026-109618 |
| Severity | HIGH |
| CVSS Score | 0.0/10 |
| CISA KEV | ✅ Yes — Actively Exploited |
| KEV Date Added | October 26, 2026 |
| Remediation Deadline | October 29, 2026 |
| EPSS Score | 100.0% exploit probability |
| EPSS Percentile | Top 99% of all CVEs |
Why This Matters
This vulnerability has been added to the CISA Known Exploited Vulnerabilities (KEV) catalog, which means threat actors are actively exploiting it in real-world attacks.
Federal agencies are required to remediate by October 29, 2026. All organizations should treat this deadline as a strong recommendation.
CISA Notes: This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://www.php.net/ ; https://www.cisa.gov/news-events/alerts/2026/10/21/critical-vulnerabilities-php-require-immediate-patching ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-109618
Exploit Prediction (EPSS)
The FIRST EPSS model rates this vulnerability at 100.0% exploit probability (Very High). This places it in the top 99% of all known CVEs by likelihood of exploitation in the next 30 days.
EPSS (Exploit Prediction Scoring System) uses real-world exploit data and machine learning to predict whether a vulnerability will be exploited. A high EPSS score is a strong signal to prioritize remediation.
Recommended Actions
- Verify exposure — Determine if your environment uses the affected software.
- Apply patches — Update to the latest version as soon as a fix is available.
- Monitor for compromise — Check logs for unusual activity.
- Meet the deadline — CISA recommends remediation by October 29, 2026.
References
CVE data aggregated from the National Vulnerability Database (NVD), CISA Known Exploited Vulnerabilities catalog, and FIRST EPSS. Analysis updated as new intelligence becomes available. Last updated: 2026-10-27.