Out-of-bounds read in Apache bRPC - CVE-2026-56386
Published: October 23, 2026
Vulnerability identifier: #VU157340
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-2026-56386
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to integer underflow and an out-of-bounds read in Apache bRPC's HTTP/2 server DATA frame parser when processing a zero-length payload with the PADDED flag set. A remote attacker can send a malformed DATA frame to underflow the unsigned fragment size and trigger a read of the pad length byte beyond the frame buffer, causing a denial of service.
Affected software
Apache bRPC
How to mitigate CVE-2026-56386
Install security update from vendor's website.
Apache bRPC - update to 1.18.0