Critical Heap Buffer Overflow Vulnerabilities in Fedora NSS and Firefox

Recent updates for Fedora 43 and 44 address critical heap buffer overflow vulnerabilities in Network Security Services (NSS) and Mozilla Firefox. The vulnerabilities, identified as Bug 1869493, affect versions 3.127.0 of NSS and Firefox 155.0. Exploitation could lead to unauthorized access or manipulation of sensitive data. Users are urged to update their systems immediately to mitigate risks. The vulnerabilities are associated with improper handling of memory, which could allow attackers to execute arbitrary code. The patches are available through the 'dnf' update program. No active exploitation has been confirmed in the wild as of the latest reports. The updates were released on September 3, 2026.

Key Points: • Critical heap buffer overflow vulnerabilities in NSS and Firefox require immediate patching. • Affected versions include NSS 3.127.0 and Firefox 155.0 on Fedora 43 and 44. • No active exploitation has been confirmed, but the vulnerabilities pose significant risks.