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Full vulnerability report · 2020
CVE-2020-6851High confidence

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

Unknown · Unknown

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 22 Sep 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 5.18% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Unknown Unknown and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

10 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Alpine v3.23v3.23 · mainopenjpegVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.2.3.1-r3Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.22v3.22 · mainopenjpegVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.2.3.1-r3Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.21v3.21 · mainopenjpegVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.2.3.1-r3Alpine Security Database ↗Source updated 3 Oct 2026
Debian trixietrixie · sourceopenjpeg2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.0-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourceopenjpeg2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.0-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourceopenjpeg2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.0-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourceopenjpeg2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.0-1Debian Security Tracker ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · esm-appsqtwebengine-opensource-srcUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · esm-appstexmakerUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archiveblenderUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2020-6851 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityopenjpeg: Heap-based buffer overflow in opj_t1_clbl_decode_processor()
136 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • openjpeg2-0:2.3.1-2.el7_7.i686 as a component of Red Hat Enterprise Linux Client (v. 7)
  • openjpeg2-0:2.3.1-2.el7_7.src as a component of Red Hat Enterprise Linux Client (v. 7)
  • openjpeg2-0:2.3.1-2.el7_7.x86_64 as a component of Red Hat Enterprise Linux Client (v. 7)
  • openjpeg2-debuginfo-0:2.3.1-2.el7_7.i686 as a component of Red Hat Enterprise Linux Client (v. 7)
  • openjpeg2-debuginfo-0:2.3.1-2.el7_7.x86_64 as a component of Red Hat Enterprise Linux Client (v. 7)
  • openjpeg2-debuginfo-0:2.3.1-2.el7_7.i686 as a component of Red Hat Enterprise Linux Client Optional (v. 7)
  • openjpeg2-debuginfo-0:2.3.1-2.el7_7.x86_64 as a component of Red Hat Enterprise Linux Client Optional (v. 7)
  • openjpeg2-devel-0:2.3.1-2.el7_7.i686 as a component of Red Hat Enterprise Linux Client Optional (v. 7)
  • openjpeg2-devel-0:2.3.1-2.el7_7.x86_64 as a component of Red Hat Enterprise Linux Client Optional (v. 7)
  • openjpeg2-devel-docs-0:2.3.1-2.el7_7.noarch as a component of Red Hat Enterprise Linux Client Optional (v. 7)
  • openjpeg2-tools-0:2.3.1-2.el7_7.i686 as a component of Red Hat Enterprise Linux Client Optional (v. 7)
  • openjpeg2-tools-0:2.3.1-2.el7_7.x86_64 as a component of Red Hat Enterprise Linux Client Optional (v. 7)
Summary
A heap-based buffer overflow flaw was found in openjpeg in the opj_t1_clbl_decode_processor in libopenjp2.so. Affecting versions through 2.3.1, the highest threat from this vulnerability is to file confidentiality and integrity as well as system availability.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-27994

No EUVD known-exploited evidence

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.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
0.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Out-of-bounds Write → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-787 ↗

CWE-787: Out-of-bounds Write. The product writes data past the end, or before the beginning, of the intended buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-787Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2020-27994Official EUVD mapping

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.

Official EUVD record ↗
BSI · German · WID-SEC-2024-2181Oracle Fusion Middleware: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Oracle Fusion Middleware ausnutzen, um die Verfügbarkeit, Vertraulichkeit und Integrität zu gefährden.

Official advisory ↗
BSI · German · WID-SEC-2023-0666OpenJPEG: Schwachstelle ermöglicht Denial of Service

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in OpenJPEG ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-001568OpenJPEG における境界外書き込みに関する脆弱性

OpenJPEG には、境界外書き込みに関する脆弱性が存在します。 本脆弱は、CVE-2020-6851 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-001059OpenJPEG における境界外書き込みに関する脆弱性

OpenJPEG には、境界外書き込みに関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
n/a
Fixed
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 13 Jan 2020 · Last source change 22 Sept 2026, 17:07 UTC · CWE-787 · Out-of-bounds Write

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2020-27994
Product sourceUnavailable
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    n/a · Fixed: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
    Red Hat Product Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2020-27994↗Red Hat Product Security security advisory↗Patch or update reference↗CVE authority or vendor reference↗Public exploit reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2020-6851 · cve.blacktree.nl