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 0.0055
EPSS Percentile 67.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-190
Status published
Products (36)
crates.io/openssl-src 0 - 111.14.0crates.io
debian/debian_linux 10.0
fujitsu/m10-1_firmware < xcp2410
fujitsu/m10-4_firmware < xcp2410
fujitsu/m10-4s_firmware < xcp2410
fujitsu/m12-1_firmware < xcp2410
fujitsu/m12-2_firmware < xcp2410
fujitsu/m12-2s_firmware < xcp2410
mcafee/epolicy_orchestrator 5.10.0 (11 CPE variants)
mcafee/epolicy_orchestrator < 5.10.0
... and 26 more
Published Feb 16, 2021
Tracked Since Feb 18, 2026