Integer underflow in Apache bRPC - CVE-2026-74755
Published: October 23, 2026
Vulnerability identifier: #VU157347
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-74755
CWE-ID: CWE-191
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service by terminating a bRPC server process.
The vulnerability exists due to integer underflow in Apache bRPC's mcpack2pb UnparsedValue::as_string() function when subtracting one from an unvalidated string value_size of zero. A remote attacker can send a crafted mcpack request containing such a string field to make resize() throw an uncaught std::length_error and abort the process.
Affected software
Apache bRPC
How to mitigate CVE-2026-74755
Install security update from vendor's website.
Apache bRPC - update to 1.18.0