CVE-2021-4156

HIGHNVD 7.18.1▲
EchelonGraph scoreMEDIUM confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2022-03-24. NVD baseline CVSS 7.1; sources differ by 1.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 7.1Exploit: None knownExposed: 0

A fix is available — apply it.

An out-of-bounds read flaw was found in libsndfile's FLAC codec functionality. An attacker who is able to submit a specially crafted file (via tricking a user to open or otherwise) to an application linked with libsndfile and using the FLAC codec, could trigger an out-of-bounds read that would most likely cause a crash but could potentially leak memory information that could be used in further exploitation of other flaws.

CVSS v3
7.1
EG Score
8.1(medium)
EG Risk
42(Track)
EG Risk 42/100SSVC: 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
Severity81% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
77%
KEV
Not listed

Published

March 23, 2022

Last Modified

December 11, 2025

References (13)

Vendor Advisories for CVE-2021-4156(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntusndfile-programs (1.0.25-10ubuntu0.16.04.3+esm2) @ xenial2026-05-26ubuntu
ubuntusndfile-programs (1.0.25-7ubuntu2.2+esm4) @ trusty2026-05-26ubuntu
redhatlibsndfile-0:1.0.28-12.el82022-05-10redhat

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

(6 across 6 ecosystems)
Debian:10(1)
PackageVulnerable rangeFixed inDependents
libsndfile1.0.28-6, 1.0.28-6+deb10u11.0.28-6+deb10u2—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
libsndfile1.0.31-2, 1.0.31-2+deb11u11.0.31-2+deb11u2—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libsndfile—1.1.0-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libsndfile—1.1.0-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libsndfile—1.1.0-1—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
libsndfile1.0.27-3, 1.0.27-3+deb9u1, 1.0.27-3+deb9u21.0.27-3+deb9u3—

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 9× in last 7d / 30× 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. 2026-09-25 02:24 UTCOSV refresh
  2. 2026-09-24 14:00 UTCEPSS rescore
  3. 2026-09-24 14:00 UTCEPSS rescore
  4. 2026-09-23 13:45 UTCEPSS rescore
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  20. 2026-09-05 17:55 UTCOSV refresh
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  1. 2026-08-30 19:14 UTCEPSS rescore
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  10. 2026-08-19 17:01 UTCEPSS rescore
  11. 2026-08-19 04:59 UTCOSV refresh
  12. 2026-08-18 13:45 UTCEPSS rescore
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  26. 2026-08-04 10:34 UTCEPSS rescore
  27. 2026-08-04 00:57 UTCOSV refresh
  28. 2026-08-03 10:33 UTCEPSS rescore
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  39. 2026-07-23 02:04 UTCEG score recompute
  40. 2026-07-22 22:51 UTCEG score recompute
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  49. 2026-07-17 19:29 UTCOSV refresh
  50. 2026-07-16 17:00 UTCEPSS rescore
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  74. 2026-06-30 23:20 UTCEPSS rescore
  75. 2026-06-29 17:32 UTCOSV refresh

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ubuntu:USN-7273-1

Frequently asked(5)

What is CVE-2021-4156?
CVE-2021-4156 is a high vulnerability published on March 23, 2022. An out-of-bounds read flaw was found in libsndfile's FLAC codec functionality. An attacker who is able to submit a specially crafted file (via tricking a user to open or otherwise) to an application linked with libsndfile and using the FLAC codec, could trigger an out-of-bounds read that would most…
When was CVE-2021-4156 disclosed?
CVE-2021-4156 was first published in the National Vulnerability Database on March 23, 2022, with the most recent update on December 11, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-4156 actively exploited?
CVE-2021-4156 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 23.1% of all scored CVEs.
What is the CVSS score of CVE-2021-4156?
CVE-2021-4156 has a CVSS v3 base score of 7.1 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.1.
How do I remediate CVE-2021-4156?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-4156, 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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