CVE-2021-33657: There is a heap overflow problem in video/SDL_pixels.c in SDL (Simple DirectMedia Layer) 2.x to 2.0.18 version

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HIGH 8.8UPGRADE

CVE-2021-33657 is a high-severity flaw (CVSS 8.8) affecting simple directmedia layer. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

There is a heap overflow problem in video/SDL_pixels.c in SDL (Simple DirectMedia Layer) 2.x to 2.0.18 versions. By crafting a malicious .BMP file, an attacker can cause the application using this library to crash, denial of service or Code execution.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Weakness	CWE-787
Published	2022-04-01
Last modified	2026-06-17

Publisher (CNA): openEuler · Vendor: libsdl

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-04-01 23:15 UTCPublished CVE record published
2026-06-17 03:54 UTCUpdated Record last modified

libsdl simple directmedia layer UPGRADE

Affected: >= 2.0.0 and <= 2.0.18

Fixed in: newer than 2.0.18

Safe to downgrade to: a release before 2.0.0

1. Check installed version

apt-cache policy simple-directmedia-layer || rpm -q simple-directmedia-layer || simple-directmedia-layer --version

2. UPGRADE to newer than 2.0.18 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade simple-directmedia-layer

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade simple-directmedia-layer

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.0.0 (Debian / Ubuntu)

apt-cache madison simple-directmedia-layer sudo apt install simple-directmedia-layer=<VERSION_BEFORE_2.0.0> sudo apt-mark hold simple-directmedia-layer

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list simple-directmedia-layer sudo dnf downgrade simple-directmedia-layer-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add simple-directmedia-layer

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-33657?

simple directmedia layer: upgrade to newer than 2.0.18. Exact commands for each OS are on this page.

Is CVE-2021-33657 being exploited?

CVE-2021-33657 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-33657 affect?

CVE-2021-33657 affects simple directmedia layer. Severity is high (CVSS 8.8). There is a heap overflow problem in video/SDL_pixels.c in SDL (Simple DirectMedia Layer) 2.x to 2.0.18 versions. By crafting a malicious .BMP file, an attacker can cause the application using this library to crash, denial of service or Code

How urgent is CVE-2021-33657?

Priority 51/100. High severity

Related CVEs

CVE-2022-4743 HIGH 7.5 UPGRADE MITIGATE A potential memory leak issue was discovered in SDL2 in GLES_CreateTexture() function in SDL_render_gles.c
CVE-2022-34568 HIGH 7.5 UPGRADE SDL v1.2 was discovered to contain a use-after-free via the XFree function at /src/video/x11/SDL_x11yuv.c.
CVE-2020-14410 MEDIUM 5.4 UPGRADE MITIGATE SDL (Simple DirectMedia Layer) through 2.0.12 has a heap-based buffer over-read in Blit_3or4_to_3or4__inversed
CVE-2020-14409 HIGH 7.8 UPGRADE MITIGATE SDL (Simple DirectMedia Layer) through 2.0.12 has an Integer Overflow (and resultant SDL_memcpy heap corruptio
CVE-2019-14906 CRITICAL 9.8 UPGRADE MITIGATE A flaw was found with the RHSA-2019:3950 erratum, where it did not fix the CVE-2019-13616 SDL vulnerability

References

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