CVE-2020-36120Public exploit

Application crash via inconsistent pixel-buffer dimensions

Published Apr 14, 2021 · Updated Aug 4, 2024

Buffer overflow in Libsixel 1.8.6 allows attackers to crash calling applications through inconsistent pixel-buffer dimensions. sixel_encoder_encode_bytes processes supplied width, height, and RGBA format values without a buffer-length argument, causing normalization to read beyond a 4,096-byte input as though it held a 400-by-300 image. Reachability requires an application to expose this buffer-and-dimensions mismatch; the published reproducer demonstrates a process abort, not code execution.

CVSS severity7.5
High
EPSS probability1.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Libsixel 1.8.6 allows attackers to crash calling applications through inconsistent pixel-buffer dimensions. sixel_encoder_encode_bytes processes supplied width, height, and RGBA format values without a buffer-length argument, causing normalization to read beyond a 4,096-byte input as though it held a 400-by-300 image. Reachability requires an application to expose this buffer-and-dimensions mismatch; the published reproducer demonstrates a process abort, not code execution.

The record

CVE
CVE-2020-36120
Published
Apr 14, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 14, 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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499Endpoint Denial of Service

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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