CVE-2021-20314

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

Stack buffer overflow in libspf2 versions below 1.2.11 when processing certain SPF macros can lead to Denial of service and potentially code execution via malicious crafted SPF explanation messages.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
3%
EPSS %ILE
86%
KEV
Not listed

Published

August 12, 2021

Last Modified

November 21, 2024

Advisory Details (5)

Auto-updated Sep 19, 2026
Patch available. Sources: redhat.
generic

libspf2: Multiple vulnerabilities (GLSA 202401-22) — Gentoo security

https://security.gentoo.org/glsa/202401-22
generic

[SECURITY] Fedora 33 Update: libspf2-1.2.11-1.20210922git4915c308.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y6T4HYXXSUQCGJB2ES6X7Q74YYF7V7XU/
generic

[SECURITY] Fedora 34 Update: libspf2-1.2.11-1.20210922git4915c308.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GFXJRHPE5OSCPTNA3ZZ4ORDHT4JQH3Y4/
generic

[SECURITY] Fedora 35 Update: libspf2-1.2.11-1.20210922git4915c308.fc35 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CMSFT2NJDZ7PATRZSQPAOGSE7JD6ELOB/
redhat Patch Available

1993070 – (CVE-2021-20314) CVE-2021-20314 libspf2: stack buffer overflow when processing SPF explanation macros

https://bugzilla.redhat.com/show_bug.cgi?id=1993070

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuspfquery (1.2.10-6ubuntu0.1~esm1) @ xenial2026-05-26ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(20 across 20 ecosystems)
Alpine:v3.11(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.12(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.13(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.14(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.15(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.16(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.17(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.18(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.19(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.20(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-r5—
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.11-r4—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.11-r4—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.11-r4—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.11-r4—
Debian:10(1)
PackageVulnerable rangeFixed inDependents
libspf21.2.10-71.2.10-7.1~deb10u1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
libspf21.2.10-7, 1.2.10-7.1~deb10u11.2.10-7.1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-7.1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-7.1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libspf2—1.2.10-7.1—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
libspf21.2.10-71.2.10-7+deb9u1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× in last 7d / 31× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 165 total refreshes for this CVE.

  1. 2026-09-24 14:00 UTCEPSS rescore
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  20. 2026-09-06 11:00 UTCOSV refresh
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  1. 2026-09-01 03:32 UTCEPSS rescore
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  11. 2026-08-19 21:34 UTCOSV refresh
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  26. 2026-08-04 16:27 UTCOSV refresh
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  39. 2026-07-23 01:56 UTCEG score recompute
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  48. 2026-07-18 10:02 UTCEPSS rescore
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  73. 2026-06-29 14:04 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2021-20314?
CVE-2021-20314 is a critical vulnerability published on August 12, 2021. Stack buffer overflow in libspf2 versions below 1.2.11 when processing certain SPF macros can lead to Denial of service and potentially code execution via malicious crafted SPF explanation messages.
When was CVE-2021-20314 disclosed?
CVE-2021-20314 was first published in the National Vulnerability Database on August 12, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-20314 actively exploited?
CVE-2021-20314 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 14.1% of all scored CVEs.
What is the CVSS score of CVE-2021-20314?
CVE-2021-20314 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-20314?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-20314, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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