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CVE-2020-25683

MEDIUMCVSS 5.9/10EPSS 86.16%

Last modified

CVE-2020-25683 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. EPSS estimates a 86.16% chance of exploitation in the next 30 days.

Description

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Metrics

CVSS 3.1
5.9/10

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

EPSS Probability
86.16%

99.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
ThekelleysDnsmasq< 2.83
FedoraprojectFedora32
FedoraprojectFedora33
DebianDebian Linux9.0
DebianDebian Linux10.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2020-25683?
A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
How severe is CVE-2020-25683?
CVE-2020-25683 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 86.16% probability of exploitation in the next 30 days.
How do I fix CVE-2020-25683?
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-2020-25683?

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

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Source: NVD / NIST