How severe is CVE-2020-6851?

CVE-2020-6851 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-6851 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-6851?

CVE-2020-6851 primarily affects Uclouvain Openjpeg. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-6851?

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-2020-6851 published?

CVE-2020-6851 was published on 2020-01-13 and last updated on 2026-06-17.

CVE-2020-6851

CVE-2020-6851 is a high-severity vulnerability in Uclouvain Openjpeg with a CVSS 3.x base score of 7.5. 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-787.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Uclouvain Openjpeg
Published: 2020-01-13
Last modified: 2026-06-17

Description

OpenJPEG through 2.3.1 has a heap-based buffer overflow in opj_t1_clbl_decode_processor in openjp2/t1.c because of lack of opj_j2k_update_image_dimensions validation.

Frequently asked questions

What is CVE-2020-6851?: OpenJPEG through 2.3.1 has a heap-based buffer overflow in opj_t1_clbl_decode_processor in openjp2/t1.c because of lack of opj_j2k_update_image_dimensions validation.
How severe is CVE-2020-6851?: CVE-2020-6851 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-6851 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-6851?: CVE-2020-6851 primarily affects Uclouvain Openjpeg. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-6851?: 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-2020-6851 published?: CVE-2020-6851 was published on 2020-01-13 and last updated on 2026-06-17.

References

Affected products (23)

cpe:2.3:a:uclouvain:openjpeg:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:7.7:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.1:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:7.7:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:7.7:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:georaster:18c:*:*:*:*:*:*:*
cpe:2.3:a:oracle:outside_in_technology:8.5.4:*:*:*:*:*:*:*
cpe:2.3:a:oracle:outside_in_technology:8.5.5:*:*:*:*:*:*:*

More vulnerabilities in Uclouvain Openjpeg

CVE-2013-4290 — Critical (CVSS 10.0): Stack-based buffer overflow in OpenJPEG before 1.5.2 allows remote attackers to have unspecified impact via unknown…
CVE-2013-4289 — Critical (CVSS 10.0): Multiple integer overflows in lib/openjp3d/jp3d.c in OpenJPEG before 1.5.2 allow remote attackers to have unspecified…
CVE-2012-3358 — Critical (CVSS 10.0): Multiple heap-based buffer overflows in the j2k_read_sot function in j2k.c in OpenJPEG 1.5 allow remote attackers to…
CVE-2025-54874 — Critical (CVSS 9.8): OpenJPEG is an open-source JPEG 2000 codec. In OpenJPEG from 2.5.1 through 2.5.3, a call to opj_jp2_read_header may…
CVE-2018-7648 — Critical (CVSS 9.8): An issue was discovered in mj2/opj_mj2_extract.c in OpenJPEG 2.3.0. The output prefix was not checked for length, which…
CVE-2017-17480 — Critical (CVSS 9.8): In OpenJPEG 2.3.0, a stack-based buffer overflow was discovered in the pgxtovolume function in jp3d/convert.c. The…

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