Bitcoin Core Discloses High-Severity Vulnerability: Some Miner Nodes May Fail to Generate Block Templates, Fix Released in 2025

November 11 — Bitcoin Core disclosed a high-severity vulnerability CVE-2025-62861, affecting versions 28.0 through 28.2 and 29.0 through 29.1. Affected miner nodes may experience transaction mempool inconsistencies after blockchain reorganizations, causing nodes to be unable to generate valid block templates until restarted. This is a node-local transaction mempool handling issue and does not mean that Bitcoin's entire network has stopped producing blocks.

The vulnerability was reported by security researcher Niklas Goegge in September 2025. Bitcoin Core released version 30.0 containing the fix on October 10, 2025, and subsequently included the fix in versions 29.2 and 28.3. Nodes still running affected versions should upgrade to a still-maintained version that includes the fix.