Uncontrolled Recursion in CBOR2 - #VU162745
Published: November 9, 2026
Vulnerability identifier: #VU162745
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: N/A
CWE-ID: CWE-674
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker to crash a service decoding untrusted CBOR data.
The vulnerability exists due to missing recursion guards in CBOR2's Rust CBORTag hashing when value-sharing references create a cyclic tag used as a map key or set element. An unauthenticated remote attacker can submit a crafted CBOR payload that exhausts the stack during decoding under default settings, terminating the worker process with a segmentation fault.
Affected software
CBOR2
Remediation
Install security update from vendor's website.
CBOR2 - update to 6.2.1