CVE-2021-3420: Fedoraproject Fedora

Critical severity, CVSS 9.8. EPSS: 2.1% chance of exploitation in the next 30 days.

A flaw was found in newlib in versions prior to 4.0.0. Improper overflow validation in the memory allocation functions mEMALIGn, pvALLOc, nano_memalign, nano_valloc, nano_pvalloc could case an integer overflow, leading to an allocation of a small buffer and then to a heap-based buffer overflow.

Affected products

• Fedoraproject Fedora: version 32 only; version 33 only; version 34 only
• Newlib Project Newlib: before 4.0.0 (fixed in 4.0.0)

Published 2021-03-05. Last modified 2026-06-17.