CVE-2026-50643

Home/CVE/8cc is vulnerable to an Out‑of‑Bounds Read due to improper handling of #line directives and GNU linemarkers. The com

CVE

8cc is vulnerable to an Out‑of‑Bounds Read due to improper handling of #line directives and GNU linemarkers. The com

8cc is vulnerable to an Out‑of‑Bounds Read due to improper handling of #line directives and GNU linemarkers. The compiler accepts attacker-controlled filename and line number metadata and later uses it without validation when accessing source line arrays. By supplying invalid or oversized line numbers, an attacker can trigger out-of-bounds memory access and a crash.

Maintainer of this project was notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Version corresponding to the commit b480958 was tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.

EPSS 0.00167

Monitor

⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)

Sigma rules0 YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Vulners Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-50643, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

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