Cyber Resilience

CVE-2020-25681

Memory Safety in Fedoraproject Fedora 32 … 33

High EPSSMemory Safety
Published
20 January 2021
Modified
04 November 2025
Patch / advisory
CVSS Score v3.1 8.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.81 99.6th percentile
Risk Priority 81 floored blend · peak EPSS

Summary

CVE-2020-25681 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Fedoraproject Fedora. Its CVSS base score is 8.1 (High).

Operationally, ranked in the top 0.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS replies such as that they…

more

are accepted as valid, could use this flaw to cause a buffer overflow with arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

CWE(s)

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
Heap buffer overflow in DNS reply processing allows remote code execution via crafted DNS responses.
T1203 Exploitation for Client Execution Executionconfidence: MEDIUM
Successful exploitation of the DNSSEC sorting flaw can lead to arbitrary code execution on the client system.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2020-25682Same product: Debian Debian Linux
CVE-2023-3180Same product: Debian Debian Linux
CVE-2023-4504Same product: Debian Debian Linux
CVE-2023-49501Same product: Fedoraproject Fedora
CVE-2025-10934Same product: Debian Debian Linux
CVE-2026-14355Same product: Debian Debian Linux
CVE-2024-3209Same product: Fedoraproject Fedora
CVE-2024-31582Same product: Fedoraproject Fedora
CVE-2023-50009Same product: Fedoraproject Fedora
CVE-2023-51795Same product: Fedoraproject Fedora

Affected Assets

thekelleys
dnsmasq
≤ 2.83
fedoraproject
fedora
32, 33
debian
debian linux
10.0, 9.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 full match
prevents

Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover heap-overflow flaws but does not prevent their introduction in code.

PR.PS-02 partial match
prevents

Timely patching removes known heap-overflow instances after they exist.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development and acceptance can detect heap overflows before release.

prevents

Secure development lifecycle mandates practices that reduce the likelihood of introducing heap overflows.

prevents

Application security requirements can specify bounds-checking and safe memory APIs that mitigate heap overflows.

prevents

Secure architecture and engineering principles include memory-safety and input-validation controls that address heap overflows.

prevents

Secure coding standards directly prescribe techniques (safe functions, bounds checks) that prevent heap-based buffer overflows.

none

Change management ensures controlled deployment of fixes for discovered heap-overflow vulnerabilities.

References