CVE-2021-21855

HIGH

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 cau...

Affects 2 products across 2 vendors.

CVSS 3.18.8
EPSS1.7%
Percentile76th
PatchPatched
CVSS Vector — Plain English Remotely exploitable over the network, low complexity, no authentication required, requires user interaction, impact contained to the vulnerable component, full confidentiality impact, full integrity impact, full availability impact.
CWE Weakness Definitions
CWE-119: Improper Restriction of Operations within Memory Buffer

Parent class for buffer-related vulnerabilities where operations exceed buffer boundaries.

CWE-680: CWE-680
Related Attack Patterns (CAPEC)
CAPEC-8 Buffer Overflow in an API Call
via CWE-119 CWE-680
CAPEC-9 Buffer Overflow in Local Command-Line Utilities
via CWE-119 CWE-680
CAPEC-10 Buffer Overflow via Environment Variables
via CWE-119 CWE-680
CAPEC-14 Client-side Injection-induced Buffer Overflow
via CWE-119 CWE-680
CAPEC-24 Filter Failure through Buffer Overflow
via CWE-119 CWE-680
Show all 14

Mapping is CWE-to-CAPEC per MITRE CAPEC 3.9.

◆ AI Analysis — automated analysis, not human-reviewed

Multiple integer overflow vulnerabilities in the MPEG-4 decoding functionality of the GPAC Project can lead to heap-based buffer overflow and memory corruption, potentially allowing an attacker to execute arbitrary code.

BSID: BS-2021-GLOBAL-241426-H • Model: /workspace/models/qwen2.5-coder-32b-instruct-bf16 • Confidence: HIGH

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Frequently Asked Questions
What is CVE-2021-21855?
Multiple integer overflow vulnerabilities in the MPEG-4 decoding functionality of the GPAC Project can lead to heap-based buffer overflow and memory corruption, potentially allowing an attacker to execute arbitrary code.
What is the CVSS score for CVE-2021-21855?
CVE-2021-21855 has CVSS 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS: 1.7%.
Is CVE-2021-21855 actively exploited?
No confirmed active exploitation of CVE-2021-21855 as of 2026-05-30.
How do I remediate CVE-2021-21855?
Priority: IMMEDIATE.
What systems are affected by CVE-2021-21855?
CVE-2021-21855 affects Debian Debian Linux; Gpac Gpac.
Vulnerability Details
CVE IDCVE-2021-21855
BSIDBS-2021-GLOBAL-241426-H BreachSpider Global ID
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published2021-08-18
Last Modified2024-11-21
ICS Relevance15%
Weakness (CWE)
Improper Restriction of Operations within Memory BufferCWE-680
SourceNVD
Official Description

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.

Source: NIST NVD / MITRE CVE Database

Attack Vector Analysis — CITED Relevance

An attacker can exploit these vulnerabilities by convincing a user to open a specially crafted MPEG-4 video file. The vulnerabilities are due to unchecked addition arithmetic leading to integer overflow.

Exploitation Likelihood: HIGH

Affected Products
VendorProductAffected Versions
Debian Debian Linux 10.0 11.0
Gpac Gpac 1.0.1
Remediation

No official vendor advisory link on record. See the CVE record →

Threat Intelligence
● Threat Intelligence Validated: October 2026 | Threat Age: 1884 Days
CISA known-exploitedNot in KEV catalog
Public ExploitNot confirmed
PoC CodeNot confirmed
AI Enrichment Record — provenance & audit hash
Model/workspace/models/qwen2.5-coder-32b-instruct-bf16
ConfidenceHIGH
Enriched At2026-05-24
SHA-512 Audit Hashf2827c512177b3ee3811af7841eb230956575e131a9a650b7370f6560463bea41f9a9637fe4f5e681621b658cb26edb23a2d0fefec22945045e11dd01604deaf
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