Bitcoin Core Discloses Medium-Severity Vulnerability That Can Halt Block Processing

TechFlow reported on November 11 that, according to a Bitcoin Core security advisory, the medium-severity vulnerability CVE-2025-62859 was disclosed on November 10. A malicious node can exploit witness data tampering in compact blocks to stall block processing on affected nodes under certain conditions.

The advisory said that when the tampering check fails, an affected node will request the block again from the same peer and wait for a 10-minute timeout. If the attacker controls three high-bandwidth peers of the victim node, or the victim node is running in blocksonly mode, the attack can be repeated indefinitely.

The vulnerability affects versions prior to 29.2 and 30.0. The fixed versions 30.0 and 29.2 were released on October 10, 2025 and October 14, 2025, respectively.

Source: TechFlow