Out-of-bounds Read in Yubico Yubihsm-Shell
CVE-2021-27217
An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3. The function does not correctly validate the embedded length field of an authenticated message received from the device. Out-of-bounds reads performed by aes_remove_padding() can crash the running process, depending on the memory layout. This could be used by an attacker to cause a client-side denial of service. The yubihsm-shell project is included in the YubiHSM 2 SDK product.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.016 (74.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 74.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/Yubico/yubihsm-shell/releases (Third Party Advisory, Release Notes)
- www.yubico.com/support/security-advisories/ysa-2021-01/ (Vendor Advisory)
- blog.inhq.net/posts/yubico-libyubihsm-vuln2 (Exploit, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-27217?
- CVE-2021-27217 is a medium-severity vulnerability in Yubico Yubihsm-Shell, classified under Out-of-bounds Read. CVSS score: 4.4/10. Published 2021-03-04.
- How severe is CVE-2021-27217?
- Medium severity. CVSS v3 base score is 4.4 out of 10.