vciy

CVE-2021-21857

INDEX BUILT · 2026-09-20

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Multiple exploitable integer overflow vulnerabilities exist within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1

CVE-2021-218574 of 4 sources documented this
27

rank 27 = 0 + 22 + 0 + 5 + 0

rank@v1 · scheduled

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.01656  ·  without this subject the record ranks 27

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 8.8, from NVD  ·  without this subject the record ranks 5

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 27

How much of the world it touches

NVD CPE configurations

3 products in the CPE ranges  ·  without this subject the record ranks 22

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 27

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$82,600over the next 30 days, if this record is yours
Movementno material movementthe record holds only daily drift and scoring model releases
Basisassumeda published average, not your estate

$82,600 = $4.99M incident cost x 1 exposure x 0.01656 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.01656EPSSNOT IN KEVas of 2026-09-20
Severity8.8 HIGHreceipt
Harmtotal lossreceipt
Exploitationnone in held sources
Defenseno fix version held
Movementscoring model changedreceipt
PLATEAU10Minimal movement since 2021-08-19, 1761 days at 0.02, as of 2026-06-15. arc-rules@v1

Foresight · where to check next

No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.

Color is a claim, not decoration:the hostile worldthe defenseno signal

Sources disagree here.

Scoring standard
TalosCVSS v3.0receipt
NVDCVSS v3.1receipt

Both shown, dated. We don't pick winners. disagreement-rules@v1

Running GPAC? Check your version

A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.

Watch this record

Matches your own product list against every record this index holds, and tells you when one of them moves.

What counts as a move

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Record your call

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AcceptDeferPatch by…Not affectedMitigated

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Harm, if it fires from the vector and the weakness

Written for the ticket you're about to file.

Reachnetwork-reachable · no privileges required · user interaction required · low attack complexityreceipt
ImpactComplete confidentiality, integrity and availability lossreceipt
Scored fromCVSS v3.0 · the CNA's vectorreceipt
Weakness classCWE-680 Integer Overflow to Buffer Overflowreceipt
Published consequencesCWE-680: Integrity, Availability, Confidentiality: Modify Memory, DoS: Crash, Exit, or Restart, Execute Unauthorized Code or Commands[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

Fixed inNo fix version in held sources, as the index stood on 15 Jun 2026.
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Nothing observed in held sources.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, the CNA8.8 HIGHreceipt
CVSS, NVD8.8 HIGHreceipt
Exploit probability0.01656 · top 24% of all CVEsreceipt
Blast breadth2 products across 2 vendorsderived
Assigned bytalosreceipt
Recorded changes19 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productGPACreceipt
Published rangesgpac 1.0.1; debian linux 10.0; debian linux 11.0receipt

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

Did this affect your environment?Answering needs an account.

Attack path

Network requestrequires user interactionn/a GPACCWE-680 weaknessFull compromise (C/I/A)C:H / I:H / A:Hexploits CWE-680data compromise

What it is stated by the CNA

Multiple exploitable integer overflow vulnerabilities exist within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. A specially crafted MPEG-4 input can cause an integer overflow due to unchecked addition arithmetic resulting in a heap-based buffer overflow that causes memory corruption. An attacker can convince a user to open a video to trigger this vulnerability. receipt

NVD's analysis a second authority

severity
8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
weakness
CWE-680; CWE-119
affected versions
gpac 1.0.1; debian linux 10.0; debian linux 11.0

check it yourself talosintelligence.com debian.org receipt

Movement the material steps

19 Aug 20210.0034
7 Mar 20230.00115 · scoring model v2023.03.01
17 Mar 20250.00457 · scoring model v2025.03.14
15 Jun 20260.01656 · scoring model v2026.06.15
Show all 19 observations
19 Aug 20210.0034
1 Sep 20210.0051
6 Jan 20220.02249
4 Feb 20220.05246
1 Apr 20220.00885
7 Mar 20230.00115
11 Mar 20230.00161
24 Mar 20240.00158
3 May 20240.00188
17 Dec 20240.00223
17 Mar 20250.00457
29 Mar 20250.01022
30 Mar 20250.00457
21 Apr 20250.00306
10 Aug 20250.00311
18 Sep 20250.00238
18 Nov 20250.00539
21 Nov 20250.00238
15 Jun 20260.01656

19 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.01656Published2021-08-18Index as of2026-06-15

The record had been public for 4 years, 9 months when this index was last written.

Published 2021-08-18 receipt · Index as of 2026-06-15 derived

Siblings and hubs

Records related to this one

Fixed with these, by one advisory

TALOS-2021-1299

Listed because one advisory covers them, not because they are the same defect. Each record's own state is on its own page.

Grouping: held values

Browse the index from here

These are index-wide views, not findings about CVE-2021-21857.

What usually comes next

Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.

Everything on this page is free. Public data. Withholding it protects nothing.