What is the CVSS score of CVE-2021-27217?

CVE-2021-27217 has a CVSS 3.1 base score of 4.4 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 1.6%.

Is there a public PoC exploit available for CVE-2021-27217?

Yes, a public proof-of-concept exploit is available for CVE-2021-27217. Prioritise patching immediately. EPSS: 1.6%.

Yubihsm Shell CVE-2021-27217

MEDIUM

Out-of-bounds Read (CWE-125)

2021-03-04 cve@mitre.org

Buffer Overflow Denial Of Service Information Disclosure Yubihsm Shell

4.4

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

4.4 MEDIUM

AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

CVE Published

Mar 04, 2021 - 18:15 nvd

MEDIUM 4.4

DescriptionNVD

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.

AnalysisAI

An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3. Rated medium severity (CVSS 4.4), this vulnerability is remotely exploitable. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Out-of-bounds Read (CWE-125), which allows attackers to read data from memory outside the intended buffer boundaries. 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. Affected products include: Yubico Yubihsm-Shell. Version information: through 2.0.3..

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate array indices and buffer lengths. Use memory-safe languages. Enable AddressSanitizer during testing.