CVE-2021-23840

HIGH

Openssl < 1.0.2y - Integer Overflow

Title source: rule

Description

Calls to EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate may overflow the output length argument in some cases where the input length is close to the maximum permissable length for an integer on the platform. In such cases the return value from the function call will be 1 (indicating success), but the output length value will be negative. This could cause applications to behave incorrectly or crash. OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).

Exploits (1)

nomisec WRITEUP
by Trinadh465 · poc
https://github.com/Trinadh465/openssl-1.1.1g_CVE-2021-23840

References (20)

Scores

CVSS v3 7.5
EPSS 0.0041
EPSS Percentile 61.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Classification

CWE
CWE-190
Status published

Affected Products (44)

openssl/openssl < 1.0.2y
debian/debian_linux
tenable/log_correlation_engine < 6.0.8
tenable/nessus_network_monitor
tenable/nessus_network_monitor
tenable/nessus_network_monitor
tenable/nessus_network_monitor
tenable/nessus_network_monitor
oracle/business_intelligence
oracle/business_intelligence
oracle/business_intelligence
oracle/business_intelligence
oracle/communications_cloud_native_core_policy
oracle/enterprise_manager_for_storage_management
oracle/enterprise_manager_ops_center
... and 29 more

Timeline

Published Feb 16, 2021
Tracked Since Feb 18, 2026