CVE-2020-12457

Name: CVE-2020-12457
Creator: NVD / NIST
Published: 2020-08-21T14:15:10.997+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.53%

Last modified Jun 17, 2026

CVE-2020-12457 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. An issue was discovered in wolfSSL before 4.5.0. It mishandles the change_cipher_spec (CCS) message processing logic for TLS 1.3. EPSS estimates a 1.53% chance of exploitation in the next 30 days.

Description

An issue was discovered in wolfSSL before 4.5.0. It mishandles the change_cipher_spec (CCS) message processing logic for TLS 1.3. If an attacker sends ChangeCipherSpec messages in a crafted way involving more than one in a row, the server becomes stuck in the ProcessReply() loop, i.e., a denial of service.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.53%

71.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-835

Affected Software

Vendor	Product	Versions
Wolfssl	Wolfssl	< 4.5.0

References

https://github.com/wolfSSL/wolfssl/pull/2927Patch, Third Party Advisory
https://github.com/wolfSSL/wolfssl/releases/tag/v4.5.0-stableThird Party Advisory
https://github.com/wolfSSL/wolfssl/pull/2927Patch, Third Party Advisory
https://github.com/wolfSSL/wolfssl/releases/tag/v4.5.0-stableThird Party Advisory

Timeline

Published: Aug 21, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-12457?

How severe is CVE-2020-12457?

CVE-2020-12457 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.53% probability of exploitation in the next 30 days.

How do I fix CVE-2020-12457?

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.

Are you affected by CVE-2020-12457?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST