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CVE-2021-20314

31
FAUCET Score

CVE-2021-20314 describes a critical stack buffer overflow vulnerability in libspf2 versions prior to 1.2.11, impacting products like Fedora and Red Hat Enterprise Linux. This flaw allows an unauthenticated attacker to trigger a Denial of Service and potentially achieve remote code execution by sending specially crafted SPF explanation messages. With a CVSS score of 9.8 (Critical), the attack requires no user interaction and has high impacts on confidentiality, integrity, and availability. While no public exploits (Metasploit, Nuclei, ExploitDB) or active exploitation have been observed, and community discussion is minimal, the high FAUCET Risk Score of 77/100 indicates its significant potential danger.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.2.11CPE matchmatch criteria
cpe:2.3:a:libspf2:libspf2:*:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
35CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.81%
Probability of exploitation in next 30 days
EPSS Percentile
85.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0281 is in the 76th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

redhatpatch availablevia nvd_reference
View patch

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/CMSFT2NJDZ7PATRZSQPAOGSE7JD6ELOB
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/GFXJRHPE5OSCPTNA3ZZ4ORDHT4JQH3Y4
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/Y6T4HYXXSUQCGJB2ES6X7Q74YYF7V7XU
security.gentoo.org / glsa/202401-22