CVE-2021-3696

MEDIUMNVD 4.54.5—
EchelonGraph scoreMEDIUM confidence

Score 4.5 from GitHub Security Advisory published 2022-07-07. NVD baseline CVSS 4.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
4.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.5Exploit: NoneExposed: 0

A fix is available — apply it.

A heap out-of-bounds write may heppen during the handling of Huffman tables in the PNG reader. This may lead to data corruption in the heap space. Confidentiality, Integrity and Availablity impact may be considered Low as it's very complex to an attacker control the encoding and positioning of corrupted Huffman entries to achieve results such as arbitrary code execution and/or secure boot circumvention. This flaw affects grub2 versions prior grub-2.12.

CVSS v3
4.5
EG Score
4.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: 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
Severity45% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
38.0%
KEV
Not listed

Published

July 6, 2022

Last Modified

November 21, 2024

References (6)

Vendor Advisories for CVE-2021-3696(5)

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

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntushim-signed (1.40.9+15.7-0ubuntu1) @ focal2026-05-25ubuntu
redhatgrub2-1:2.02-99.el8_4.92022-06-16redhat
redhatgrub2-1:2.06-27.el9_0.72022-06-16redhat
redhatgrub2-1:2.02-123.el8_6.82022-06-16redhat
redhatgrub2-1:2.02-87.el8_1.102022-06-16redhat
redhatgrub2-1:2.02-87.el8_2.102022-06-16redhat

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.

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 13× in last 7d / 51× 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 108 total refreshes for this CVE.

  1. 2026-07-23 02:03 UTCEG score recompute
  2. 2026-07-22 22:49 UTCEG score recompute
  3. 2026-07-22 14:06 UTCEPSS rescore
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  46. 2026-06-11 22:25 UTCOSV refresh
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Frequently asked(5)

What is CVE-2021-3696?
CVE-2021-3696 is a medium vulnerability published on July 6, 2022. A heap out-of-bounds write may heppen during the handling of Huffman tables in the PNG reader. This may lead to data corruption in the heap space. Confidentiality, Integrity and Availablity impact may be considered Low as it's very complex to an attacker control the encoding and positioning of…
When was CVE-2021-3696 disclosed?
CVE-2021-3696 was first published in the National Vulnerability Database on July 6, 2022, 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-2021-3696 actively exploited?
CVE-2021-3696 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 38.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-3696?
CVE-2021-3696 has a CVSS v3 base score of 4.5 (NVD).
How do I remediate CVE-2021-3696?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3696, 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.

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