BlackTreeCVE Intelligence
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Full vulnerability report · 2021
CVE-2021-42836High confidence

GJSON before 1.9.3 allows a ReDoS (regular expression denial of service) attack

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 4 Aug 2024

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 2.42% 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

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 · sourcegolang-github-tidwall-gjsonVendor fix publishedDebian records a fixed source-package version for this release.1.14.4-2Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourcegolang-github-tidwall-gjsonVendor fix publishedDebian records a fixed source-package version for this release.1.14.4-2Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourcegolang-github-tidwall-gjsonVendor fix publishedDebian records a fixed source-package version for this release.1.14.4-2Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcegolang-github-tidwall-gjsonVendor fix publishedDebian records a fixed source-package version for this release.1.14.4-2Debian Security Tracker ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivegolang-github-tidwall-gjsonUnder 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
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-2021-2240

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

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

GJSON before 1.9.3 allows a ReDoS (regular expression denial of service) attack.

What

GJSON before 1.9.3 allows a ReDoS (regular expression denial of service) attack.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

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

What

GJSON before 1.9.3 allows a ReDoS (regular expression denial of service) attack.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation without authentication or 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 → Uncontrolled Resource Consumption → disrupt the affected service
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-400 ↗

CWE-400: Uncontrolled Resource Consumption. The product does not properly control the allocation and maintenance of a limited resource.

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.
NetworkUnauthenticatedDenial of serviceCWE-400Public exploit reference
A

Official authority intelligence

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

BSI · German · WID-SEC-2022-0510IBM DB2: Mehrere Schwachstellen

Ein entfernter, anonymer, authentisierter oder lokaler Angreifer kann mehrere Schwachstellen in IBM DB2 ausnutzen, um Dateien zu manipulieren, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand auszulösen, willkürlichen Code mit erhöhten Rechten auszuführen, Informationen falsch darzustellen und beliebigen Code auszuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20211027Security Bulletin 27 Oct 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 27 Oct 2021, published on 27 October 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0199Multiples vulnérabilités dans les produits VMware

d?id=CVE-2021-42374 Référence CVE CVE-2021-42376 https://www.cve.org/CVERecord?id=CVE-2021-42376 Référence CVE CVE-2021-42378 https://www.cve.org/CVERecord?id=CVE-2021-42378 Référence CVE CVE-2021-42379 https://www.cve.org/CVERecord?id=CVE-2021-42379 Référence CVE CVE-2021-42381 https://www.cve.org/CVERecord?id=CVE-2021-42381 Référence CVE CVE-2021-42382 https://www.cve.org/CVERecord?id=CVE-2021-42382 Référence CVE CVE-2021-42384 https://www.cve.org/CVERecord?id=CVE-2021-42384 Référence CVE CVE-2021-42385 https://www.cve.org/CVERecord?id=CVE-2021-42385 Référence CVE CVE-2021-42386 https://www.cve.org/CVERecord?id=CVE-2021-42386 Référence CVE CVE-2021-42836 https://www.cve.org/CVERecord?id=CVE-2021-42836 Référence CVE CVE-2021-43565 https://www.cve.org/CVERecord?id=CVE-2021-43565 Référence CVE CVE-2021-43816 https://www.cve.org/CVERecord?id=CVE-2021-43816 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-2021-46848 https://www.cve.org/CVERecord?id=CVE-2021-46848 Référence CVE CVE-2022-0563 https://www.cve.org/CVERecord?id=CVE-2022-0563 Référence CVE CVE-2022-0778 https://www.cve.org/CVERecord?id=CVE-2022-0778 Référence CVE CVE-2022-1271 https://www.cve.org/CVERecord?id=CVE-2

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0976Multiples vulnérabilités dans les produits IBM

ord?id=CVE-2021-37712 Référence CVE CVE-2021-37713 https://www.cve.org/CVERecord?id=CVE-2021-37713 Référence CVE CVE-2021-38297 https://www.cve.org/CVERecord?id=CVE-2021-38297 Référence CVE CVE-2021-39008 https://www.cve.org/CVERecord?id=CVE-2021-39008 Référence CVE CVE-2021-39293 https://www.cve.org/CVERecord?id=CVE-2021-39293 Référence CVE CVE-2021-41771 https://www.cve.org/CVERecord?id=CVE-2021-41771 Référence CVE CVE-2021-41772 https://www.cve.org/CVERecord?id=CVE-2021-41772 Référence CVE CVE-2021-4189 https://www.cve.org/CVERecord?id=CVE-2021-4189 Référence CVE CVE-2021-42248 https://www.cve.org/CVERecord?id=CVE-2021-42248 Référence CVE CVE-2021-42836 https://www.cve.org/CVERecord?id=CVE-2021-42836 Référence CVE CVE-2021-44716 https://www.cve.org/CVERecord?id=CVE-2021-44716 Référence CVE CVE-2022-0391 https://www.cve.org/CVERecord?id=CVE-2022-0391 Référence CVE CVE-2022-1471 https://www.cve.org/CVERecord?id=CVE-2022-1471 Référence CVE CVE-2022-23772 https://www.cve.org/CVERecord?id=CVE-2022-23772 Référence CVE CVE-2022-23773 https://www.cve.org/CVERecord?id=CVE-2022-23773 Référence CVE CVE-2022-23806 https://www.cve.org/CVERecord?id=CVE-2022-23806 Référence CVE CVE-2022-24675 https://www.cve.org/CVERecord?id=CVE-2022-24675 Référence CVE CVE-2022-24921 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-591Multiples vulnérabilités dans les produits IBM

rg/CVERecord?id=CVE-2021-4083 Référence CVE CVE-2021-41190 https://www.cve.org/CVERecord?id=CVE-2021-41190 Référence CVE CVE-2021-4154 https://www.cve.org/CVERecord?id=CVE-2021-4154 Référence CVE CVE-2021-4155 https://www.cve.org/CVERecord?id=CVE-2021-4155 Référence CVE CVE-2021-4157 https://www.cve.org/CVERecord?id=CVE-2021-4157 Référence CVE CVE-2021-41864 https://www.cve.org/CVERecord?id=CVE-2021-41864 Référence CVE CVE-2021-4197 https://www.cve.org/CVERecord?id=CVE-2021-4197 Référence CVE CVE-2021-4203 https://www.cve.org/CVERecord?id=CVE-2021-4203 Référence CVE CVE-2021-42248 https://www.cve.org/CVERecord?id=CVE-2021-42248 Référence CVE CVE-2021-42836 https://www.cve.org/CVERecord?id=CVE-2021-42836 Référence CVE CVE-2021-43565 https://www.cve.org/CVERecord?id=CVE-2021-43565 Référence CVE CVE-2021-43784 https://www.cve.org/CVERecord?id=CVE-2021-43784 Référence CVE CVE-2021-44716 https://www.cve.org/CVERecord?id=CVE-2021-44716 Référence CVE CVE-2021-44733 https://www.cve.org/CVERecord?id=CVE-2021-44733 Référence CVE CVE-2021-44907 https://www.cve.org/CVERecord?id=CVE-2021-44907 Référence CVE CVE-2021-45485 https://www.cve.org/CVERecord?id=CVE-2021-45485 Référence CVE CVE-2021-45486 https://www.cve.org/CVERecord?id=CVE-2021-45486 Référence CVE CVE-2022-0185 https://www.cve.org/CVERecord?id=C

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-014360GJSON におけるリソースの枯渇に関する脆弱性

GJSON には、リソースの枯渇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
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.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
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 Oct 2021 · Last source change 4 Aug 2024, 03:38 UTC · CWE-400 · Uncontrolled Resource Consumption

CVE recordCVE.org · 5.1
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-2021-2240
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
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-2240↗Public exploit reference↗Patch or update reference↗Patch or update 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-2021-42836 · cve.blacktree.nl