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CVE-2025-69873: ajv (Another JSON Schema Validator) before 8.18.0 is vulnerable to Regular Expression Denial of Service (Re...

ajv (Another JSON Schema Validator) before 8.18.0 is vulnerable to Regular Expression Denial of Service (ReDoS) when the $data option is enabled. The pattern keyword accepts runtime data via JSON Pointer syntax ($data reference), which is passed directly to the JavaScript RegExp() constructor without validation. An attacker can inject a malicious regex pattern (e.g., "^(a|a)*$") combined with crafted input to cause catastrophic backtracking. A 31-character payload causes approximately 44 seconds of CPU blocking, with each additional character doubling execution time. This enables complete denial of service with a single HTTP request against any API using ajv with $data: true for dynamic schema validation. This issue is also fixed in version 6.14.0.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2025-69873 is a denial-of-service issue in Ajv. If an application enables dynamic schema data and lets untrusted input influence regex validation, one crafted request can consume CPU and make the service unavailable. The business risk is outage, not data theft or integrity loss.

Executive priority

Treat as high priority for internet-facing Node.js APIs that use Ajv dynamic validation. For systems only carrying Ajv transitively without $data usage, prioritize inventory and confirmation before emergency change windows.

Technical view

Ajv before 8.18.0 is reported vulnerable when $data is enabled. Runtime data supplied through JSON Pointer can reach the JavaScript RegExp constructor for the pattern keyword without validation, enabling catastrophic backtracking. The bundle also states the issue is fixed in 6.14.0 for the v6 line.

Likely exposure

Likely exposure is narrower than a normal dependency finding. Systems are at risk when they use Ajv with $data: true and allow attacker-controlled values to become regex patterns during validation, especially in public APIs. Simple presence of Ajv alone is not enough evidence of exploitability.

Exploitation context

The source bundle does not cite CISA KEV listing or active exploitation. It describes network, low-complexity, unauthenticated denial of service where a vulnerable API performs dynamic schema validation with attacker-influenced regex input. Avoid assuming exploit activity without additional evidence.

Researcher notes

Key uncertainty is affected-range detail: the description says before 8.18.0 and fixed in 6.14.0, while bundle metadata also contains limited affected version entries. Validate against the GitHub advisory, Ajv pull requests, and vendor package advisories before final scoping.

Mitigation direction

  • Upgrade Ajv to 8.18.0 or later where applicable.
  • For Ajv v6 deployments, move to 6.14.0 if still supported.
  • Disable $data unless dynamic schema references are required.
  • Do not allow untrusted data to define regex patterns.
  • Review vendor advisories for distribution-specific fixed packages.
  • Apply Red Hat errata where Red Hat packages are in use.

Validation and detection

  • Inventory applications and lockfiles for Ajv versions in use.
  • Check whether Ajv is initialized with $data: true.
  • Review schemas using pattern with $data references.
  • Identify public APIs that validate attacker-submitted JSON.
  • Confirm upgraded package versions in deployed artifacts.
  • Monitor service CPU saturation after remediation.
Prepared
Confidence
medium
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-1333: Exact CWE lookup

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cwe · low confidence lookup

CWE-400: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2025-69873 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

3CVSS vectors
5Timeline events
2ADP providers
33Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical Impact: partial

CVSS vector scores

3 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6CISA-ADP
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP
2.9CVSS 3.1LowCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L1.41.4mitre

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2025-69873Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPajv: ReDoS via $data reference
other:Red Hat severity ratingcvssV3_1
  • 2026-02-11T19:01:32.953Z: Reported to Red Hat.
  • 2026-02-11T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
ajv.jsajv0, 7.0.0unaffected
Weakness

CWE details

CWE-1333CWE-400

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-1333 · source CWE mapping

Inefficient Regular Expression Complexity

Inefficient Regular Expression Complexity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-400 · source CWE mapping

Uncontrolled Resource Consumption

Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs