CVE-2021-23840

HIGH

CVSS v3.1: 7.5 · EPSS: 0.0062 (70.1 percentile)

NetworkNo privilegesNo user interactionInteger OverflowVendor advisory ref

Source data as of:

At a glance

Severity
HIGH
CVSS
7.5 v3.1 · NVD
EPSS
0.0062 (70.1 percentile) · FIRST.org
CISA KEV
No
Type
Integer Overflow · NVD CWE
Attack conditions (CVSS vector)
NetworkNo privilegesNo user interaction · Source: NVD Vector
Affected vendors
openssl, nodejs, mcafee, oracle, debian, fujitsu, tenable
Published
2021-02-16 · Modified: 2026-04-16

CVSS / EPSS / KEV

CVSS v3.1 7.5 / 10 HIGH Source: NVD
EPSS 0.0062 70.1 percentile Source: FIRST.org
CISA KEV No Source: CISA

Source — CVSS: NVD · EPSS: FIRST.org · KEV: CISA. Data & Sources

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).

Record details

CVE ID
CVE-2021-23840
CVSS (v3.1)
7.5 (HIGH)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploitability subscore
3.9
Impact subscore
3.6
EPSS
0.0062 (70.1 percentile) — 2026-04-17
CISA KEV
No
Weakness (CWE)
CWE-190
Affected vendors
openssl, nodejs, mcafee, oracle, debian, fujitsu, tenable
Affected configurations (CPE)
55
Published
2021-02-16
Modified
2026-04-16
Status
Modified

References

Reference URLs as listed by NVD, grouped by a mechanical match on the link's host/pattern. Labels describe the link type only.