CVE-2020-25577

Name: CVE-2020-25577
Creator: NVD / NIST
Published: 2021-03-29T20:15:12.86+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.50%

Last modified Jun 17, 2026

CVE-2020-25577 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. In FreeBSD 12.2-STABLE before r368250, 11.4-STABLE before r368253, 12.2-RELEASE before p1, 12.1-RELEASE before p11 and 11.4-RELEASE before p5 rtsold(8) does not verify that the RDNSS option does not extend past the end of the received packet before processing its contents. While the kernel currently ignores such malformed packets, it passes them to userspace programs. EPSS estimates a 1.50% chance of exploitation in the next 30 days.

Description

In FreeBSD 12.2-STABLE before r368250, 11.4-STABLE before r368253, 12.2-RELEASE before p1, 12.1-RELEASE before p11 and 11.4-RELEASE before p5 rtsold(8) does not verify that the RDNSS option does not extend past the end of the received packet before processing its contents. While the kernel currently ignores such malformed packets, it passes them to userspace programs. Any programs expecting the kernel to do validation may be vulnerable to an overflow.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

1.50%

70.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-120

Affected Software

Vendor	Product	Versions
Freebsd	Freebsd	11.4
Freebsd	Freebsd	12.1
Freebsd	Freebsd	12.2

References

https://security.FreeBSD.org/advisories/FreeBSD-SA-20:32.rtsold.ascVendor Advisory
https://security.netapp.com/advisory/ntap-20210423-0001/Third Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-20:32.rtsold.ascVendor Advisory
https://security.netapp.com/advisory/ntap-20210423-0001/Third Party Advisory

Timeline

Published: Mar 29, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-25577?

How severe is CVE-2020-25577?

CVE-2020-25577 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.50% probability of exploitation in the next 30 days.

How do I fix CVE-2020-25577?

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-2020-25577?

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

Scan your code now

Source: NVD / NIST