Executive Summary
An IMAP FETCH response line indicates the size of the returned data, in number of bytes. When that response says the data is zero bytes, libcurl would pass on that (non-existing) data with a pointer and the size (zero) to the deliver-data function. libcurl's deliver-data function treats zero as a magic number and invokes strlen() on the data to figure out the length. The strlen() is called on a heap based buffer that might not be zero terminated so libcurl might read beyond the end of it into whatever memory lies after (or just crash) and then deliver that to the application as if it was actually downloaded.
Why It Matters
CVE-2017-1000257 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9.1/10
EPSS (Exploit Prediction): 1.0% probability of exploitation in the next 30 days.
Affected Technologies
Vendors: haxx, debian
Products: libcurl, debian_linux
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2017-1000257 and similar vulnerabilities.
References & Sources
AI Security Advisor
Powered by Gemini
Get AI-powered security recommendations tailored to this specific threat — including risk assessment, detection guidance, MITRE ATT&CK mapping, and actionable remediation steps.
Affected Products
Sources
Protect Your Organization
Monitor CVEs, scan for vulnerabilities, and get real-time threat alerts — all in one platform.
Get instant alerts on Telegram
Join our public channel for real-time critical CVE alerts.
Follow @vulnios