How severe is CVE-2021-33815?

CVE-2021-33815 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-33815 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33815?

CVE-2021-33815 affects Ffmpeg. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33815?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-33815 published?

CVE-2021-33815 was published on 2021-06-03 and last updated on 2026-06-17.

CVE-2021-33815

CVE-2021-33815 is a high-severity vulnerability in Ffmpeg with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-129.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-129
Affected product: Ffmpeg
Published: 2021-06-03
Last modified: 2026-06-17

Description

dwa_uncompress in libavcodec/exr.c in FFmpeg 4.4 allows an out-of-bounds array access because dc_count is not strictly checked.

Frequently asked questions

What is CVE-2021-33815?: dwa_uncompress in libavcodec/exr.c in FFmpeg 4.4 allows an out-of-bounds array access because dc_count is not strictly checked.
How severe is CVE-2021-33815?: CVE-2021-33815 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-33815 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33815?: CVE-2021-33815 affects Ffmpeg. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33815?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-33815 published?: CVE-2021-33815 was published on 2021-06-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ffmpeg:ffmpeg:4.4:*:*:*:*:*:*:*

More vulnerabilities in Ffmpeg

CVE-2013-0864 — Critical (CVSS 10.0): The gif_copy_img_rect function in libavcodec/gifdec.c in FFmpeg before 1.1.2 performs an incorrect calculation for an…
CVE-2013-4265 — Critical (CVSS 10.0): The av_reallocp_array function in libavutil/mem.c in FFmpeg before 2.0.1 has an unspecified impact and remote vectors…
CVE-2013-0873 — Critical (CVSS 10.0): The read_header function in libavcodec/shorten.c in FFmpeg before 1.1.3 allows remote attackers to have an unspecified…
CVE-2013-0872 — Critical (CVSS 10.0): The swr_init function in libswresample/swresample.c in FFmpeg before 1.1.3 allows remote attackers to have an…
CVE-2011-3937 — Critical (CVSS 10.0): The H.263 codec (libavcodec/h263dec.c) in FFmpeg 0.7.x before 0.7.12, 0.8.x before 0.8.11, and unspecified versions…
CVE-2012-2804 — Critical (CVSS 10.0): Unspecified vulnerability in libavcodec/indeo3.c in FFmpeg before 0.11 and Libav 0.8.x before 0.8.5 has unknown impact…

All CVEs affecting Ffmpeg →

Other CWE-129 (Improper Validation of Array Index) vulnerabilities

CVE-2020-27485 — Critical (CVSS 9.9): Garmin Forerunner 235 before 8.20 is affected by: Array index error. The component is: ConnectIQ TVM. The attack vector…
CVE-2020-27483 — Critical (CVSS 9.9): Garmin Forerunner 235 before 8.20 is affected by: Array index error. The component is: ConnectIQ TVM. The attack vector…
CVE-2026-21413 — Critical (CVSS 9.8): A heap-based buffer overflow vulnerability exists in the lossless_jpeg_load_raw functionality of LibRaw Commit 0b56545…
CVE-2025-27034 — Critical (CVSS 9.8): Memory corruption while selecting the PLMN from SOR failed list.
CVE-2025-3357 — Critical (CVSS 9.8): IBM Tivoli Monitoring 6.3.0.7 through 6.3.0.7 Service Pack 19 could allow a remote attacker to execute arbitrary code…
CVE-2024-45569 — Critical (CVSS 9.8): Memory corruption while parsing the ML IE due to invalid frame content.

Browse all CWE-129 (Improper Validation of Array Index) vulnerabilities →