CVE-2021-27217
Out-of-bounds reads performed by aes_remove_padding() can crash the running process, depending on the memory layout.
Does this matter?
Lower severity and a low EPSS score (1.59%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 4.4 MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.59% probability · 76th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-125
- Affected
- yubico/yubihsm-shell
- Source
- cve@mitre.org
EPSS 1.6% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://blog.inhq.net/posts/yubico-libyubihsm-vuln2Exploit, Third Party Advisory
- https://github.com/Yubico/yubihsm-shell/releasesRelease Notes, Third Party Advisory
- https://www.yubico.com/support/security-advisories/ysa-2021-01/Vendor Advisory
- https://blog.inhq.net/posts/yubico-libyubihsm-vuln2Exploit, Third Party Advisory
- https://github.com/Yubico/yubihsm-shell/releasesRelease Notes, Third Party Advisory
- https://www.yubico.com/support/security-advisories/ysa-2021-01/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.