CVE-2021-33657Public exploitNetwork attack vector

Code execution via undersized palette map

Published Apr 1, 2022 · Updated Aug 3, 2024

Heap buffer overflow in Simple DirectMedia Layer 2.0.0 through 2.0.18 allows attackers to execute code via a crafted BMP image. Blit1to3 uses a BMP-controlled palette index to read from a map that Map1toN sizes from the attacker-controlled biClrUsed value, so an out-of-range pixel accesses heap memory beyond the allocation. An application must load and convert the image; successful triggering can crash the process or execute code in that application's security context.

CVSS severity8.8
High
EPSS probability2.05%
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 Simple DirectMedia Layer 2.0.0 through 2.0.18 allows attackers to execute code via a crafted BMP image. Blit1to3 uses a BMP-controlled palette index to read from a map that Map1toN sizes from the attacker-controlled biClrUsed value, so an out-of-range pixel accesses heap memory beyond the allocation. An application must load and convert the image; successful triggering can crash the process or execute code in that application's security context.

The record

CVE
CVE-2021-33657
Published
Apr 1, 2022
Updated
Aug 3, 2024
Vendor
Simple DirectMedia Layer
Product
Simple DirectMedia Layer
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.x to 2.0.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Simple DirectMedia Layer · Simple DirectMedia Layerversion=2.x to 2.0.18

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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
T1203Exploitation for Client Execution

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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