CVE-2020-19491

Denial of service via GIF extension block corruption

Published Jul 21, 2021 · Updated Aug 4, 2024

An invalid memory access in sam2p 0.49.4 allows local users to cause denial of service via a crafted GIF input. During GIF parsing, cgif.c passes the wrong structure pointer to AddExtensionBlock, corrupting extension-block state and triggering a segmentation fault. Exploitation requires processing attacker-controlled image data; the demonstrated consequence is process interruption, while other impact remains unspecified.

CVSS severity7.8
High
EPSS probability1.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An invalid memory access in sam2p 0.49.4 allows local users to cause denial of service via a crafted GIF input. During GIF parsing, cgif.c passes the wrong structure pointer to AddExtensionBlock, corrupting extension-block state and triggering a segmentation fault. Exploitation requires processing attacker-controlled image data; the demonstrated consequence is process interruption, while other impact remains unspecified.

The record

CVE
CVE-2020-19491
Published
Jul 21, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 21, 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 vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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