BlackTreeCVE Intelligence
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Full vulnerability report · 2023
CVE-2021-46312High confidence

An issue was discovered IW44EncodeCodec.cpp in djvulibre 3.5.28 in allows attackers to cause a denial of service via divide by zero

Unknown · Unknown

6.5MediumCVSS 3.1
Recommended action
Within 7 days

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

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:High, raised one band.upgradedsince 4 Nov 2025

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • EPSS is 1.04% for the current model date.

Compensating controls

  • 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. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  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 30 daysRemediation target: Within 180 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

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

5 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
Debian trixietrixie · sourcedjvulibreVendor fix publishedDebian records a fixed source-package version for this release.3.5.28-2.2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcedjvulibreVendor fix publishedDebian records a fixed source-package version for this release.3.5.28-2.2~deb12u1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcedjvulibreVendor fix publishedDebian records a fixed source-package version for this release.3.5.28-2.2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcedjvulibreVendor fix publishedDebian records a fixed source-package version for this release.3.5.28-2.2Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivedjvulibreVendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.3.5.28-2ubuntu0.24.04.2Canonical Ubuntu Security ↗Source updated 5 Oct 2026
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-2021-33001

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

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

Fix not verified
01

What, why and how

An issue was discovered IW44EncodeCodec.cpp in djvulibre 3.5.28 in allows attackers to cause a denial of service via divide by zero.

What

An issue was discovered IW44EncodeCodec.cpp in djvulibre 3.5.28 in allows attackers to cause a denial of service via divide by zero.

Why

The product divides a value by zero.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may disrupt the affected service.

What

An issue was discovered IW44EncodeCodec.cpp in djvulibre 3.5.28 in allows attackers to cause a denial of service via divide by zero.

Why

The product divides a value by zero.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may disrupt the affected service.

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 → Divide By Zero → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
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-369 ↗

CWE-369: Divide By Zero. The product divides a value by zero.

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:R/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.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.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.
NetworkUnauthenticatedDenial of serviceCWE-369Public exploit reference
A

Official authority intelligence

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

Cyber Security Agency of Singapore · English · CSA-SB-20230823Security Bulletin 23 Aug 2023

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 23 Aug 2023, published on 23 August 2023. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0969Multiples vulnérabilités dans les produits VMware

d?id=CVE-2021-43618 Référence CVE CVE-2021-43809 https://www.cve.org/CVERecord?id=CVE-2021-43809 Référence CVE CVE-2021-44716 https://www.cve.org/CVERecord?id=CVE-2021-44716 Référence CVE CVE-2021-44717 https://www.cve.org/CVERecord?id=CVE-2021-44717 Référence CVE CVE-2021-44964 https://www.cve.org/CVERecord?id=CVE-2021-44964 Référence CVE CVE-2021-45346 https://www.cve.org/CVERecord?id=CVE-2021-45346 Référence CVE CVE-2021-45931 https://www.cve.org/CVERecord?id=CVE-2021-45931 Référence CVE CVE-2021-45942 https://www.cve.org/CVERecord?id=CVE-2021-45942 Référence CVE CVE-2021-46310 https://www.cve.org/CVERecord?id=CVE-2021-46310 Référence CVE CVE-2021-46312 https://www.cve.org/CVERecord?id=CVE-2021-46312 Référence CVE CVE-2021-46828 https://www.cve.org/CVERecord?id=CVE-2021-46828 Référence CVE CVE-2021-46848 https://www.cve.org/CVERecord?id=CVE-2021-46848 Référence CVE CVE-2022-0156 https://www.cve.org/CVERecord?id=CVE-2022-0156 Référence CVE CVE-2022-0158 https://www.cve.org/CVERecord?id=CVE-2022-0158 Référence CVE CVE-2022-0284 https://www.cve.org/CVERecord?id=CVE-2022-0284 Référence CVE CVE-2022-0319 https://www.cve.org/CVERecord?id=CVE-2022-0319 Référence CVE CVE-2022-0351 https://www.cve.org/CVERecord?id=CVE-2022-0351 Référence CVE CVE-2022-0391 https://www.cve.org/CVERecord?id=CVE-2022-03

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2023-022601DjVuLibre Project の DjVuLibre におけるゼロ除算に関する脆弱性

DjVuLibre Project の DjVuLibre には、ゼロ除算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.
Fix not verified
Affected
n/a
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
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 22 Aug 2023 · Last source change 4 Nov 2025, 17:12 UTC · CWE-369 · Divide By Zero

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-2021-33001
Product sourceUnavailable
Remediation sourceCVE/CNA references
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 ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2021-33001↗CISA Vulnrichment SSVC evidence↗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-2021-46312 · cve.blacktree.nl