CVE-2020-26939

Description

In Legion of the Bouncy Castle BC before 1.55 and BC-FJA before 1.0.2, attackers can obtain sensitive information about a private exponent because of Observable Differences in Behavior to Error Inputs. This occurs in org.bouncycastle.crypto.encodings.OAEPEncoding. Sending invalid ciphertext that decrypts to a short payload in the OAEP Decoder could result in the throwing of an early exception, potentially leaking some information about the private exponent of the RSA private key performing the encryption.

How to fix CVE-2020-26939

To remediate CVE-2020-26939, upgrade the affected package to a fixed version below.

—upgrade to 1.56-1+deb9u3 or later
—upgrade to 1.61-1 or later
—upgrade to 1.0.2 or later
—upgrade to 1.61 or later
—upgrade to 1.61 or later
—upgrade to 1.61 or later
—upgrade to 1.61 or later
—upgrade to 1.61 or later
—upgrade to 1.61 or later
—upgrade to 1.61 or later

Is CVE-2020-26939 being exploited?

Low — EPSS is 2.4%, meaning exploitation activity has not been observed at scale.

Affected packages (10)

from 0, < 1.56-1+deb9u3
from 0, < 1.61-1
from 0, < 1.0.2
from 0, < 1.61
from 0, < 1.61
from 0, < 1.61
from 0, < 1.61
from 0, < 1.61
from 0, < 1.61
from 0, < 1.61

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	MEDIUM5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N