CVE-2020-21603Public exploitNetwork attack vector

Decoder crash via out-of-bounds pixel read

Published Sep 16, 2021 · Updated Aug 4, 2024

Heap buffer overflow in libde265 1.0.4 allows remote attackers to crash a decoding process by supplying a crafted HEVC file. During inter-prediction decoding, put_qpel_0_0_fallback_16 in fallback-motion.cc reads a 16-bit value immediately beyond an allocated image buffer. A user or consuming application must open the file; the demonstrated consequence is an AddressSanitizer abort, with no sourced code-execution claim.

CVSS severity6.5
Medium
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in libde265 1.0.4 allows remote attackers to crash a decoding process by supplying a crafted HEVC file. During inter-prediction decoding, put_qpel_0_0_fallback_16 in fallback-motion.cc reads a 16-bit value immediately beyond an allocated image buffer. A user or consuming application must open the file; the demonstrated consequence is an AddressSanitizer abort, with no sourced code-execution claim.

The record

CVE
CVE-2020-21603
Published
Sep 16, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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