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CVE-2020-26939

MEDIUMCVSS 5.3/10EPSS 0.91%

Last modified

CVE-2020-26939 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, 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. EPSS estimates a 0.91% chance of exploitation in the next 30 days.

Description

In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, 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.

Metrics

CVSS 3.1
5.3/10

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

EPSS Probability
0.91%

55.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
BouncycastleFips Java Api< 1.0.1.2
BouncycastleLegion-Of-The-Bouncy-Castle< 1.61

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2020-26939?
In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, 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 severe is CVE-2020-26939?
CVE-2020-26939 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.91% probability of exploitation in the next 30 days.
How do I fix CVE-2020-26939?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST