CASCACascade Atlas

Evidence dossier

CVE-2021-23758

Deserialization of Untrusted Data

Exploited in the wild (CISA KEV since Aug 26, 2026). NVD reports CVSS 3.1 9.8. Severity assessments differ within at least one CVSS version. EPSS estimates 83.6% exploit likelihood as of Aug 27, 2026.

78.5–88.1Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

All versions of package ajaxpro.2 are vulnerable to Deserialization of Untrusted Data due to the possibility of deserialization of arbitrary .NET classes, which can be abused to gain remote code execution.

State
PUBLISHED
Published
Dec 3, 2021
Updated
Sep 17, 2024
Evidence coverage
72%

Evidence chronology

What was known when

Download this view's receipt →
  1. Source dateSource date omittedFirst observed by CASCA
    CVE Program

    Record text: CVE Program Container

    Inspect raw assertion
    Field
    container
    Value
    CVE Program Container
    Original evidence ↗
  2. Source dateSource date omittedFirst observed by CASCA
    snyk

    Record text: Deserialization of Untrusted Data

    Inspect raw assertion
    Field
    container
    Value
    Deserialization of Untrusted Data
    Original evidence ↗
  3. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Ajax.NET Professional Deserialization of Untrusted Data Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 83.63% probability · 99.67th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.836330000000; percentile 0.996660000000
    Original evidence ↗

Assessments differ

NVD9.8CVSS 3.1 · source date omitted
NVD7.5CVSS 2.0 · source date omitted
report@snyk.io8.1CVSS 3.1 · source date omitted

Values are shown separately by source and CVSS version.

ExploitationCatalog member

CISA KEV · catalog date Aug 26, 2026 · first observed Aug 27, 2026

Exploit likelihood83.63%

FIRST EPSS · score date Aug 27, 2026 · 99.7th percentile · first observed Aug 27, 2026

SeverityAssessments differ

NVD · CVSS 3.1 · first observed Aug 26, 2026 · values shown separately below

Evidence detail

Source limits and decisions

Why each evidence state has this value

casca-unknown-reasons-v1
Exploitation statusEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Severity assessmentAssessments differ

Eligible assertions materially conflict and remain visible side by side.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Aug 27, 2026
Resolution
Resolve conflict
Affected productsSource-reported scope

The cited source assertion is retained while canonical product linkage remains open.

Revision
casca-factor-d-obligations-v1
Cutoff
Aug 27, 2026
Resolution
Resolve identity

Source comparison

Who said what

CVE ProgramDerivative copy
Record text

CVE Program Container

Inspect raw assertion
Field
container
Value
CVE Program Container
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
snykOriginal assertion
Record text

Deserialization of Untrusted Data

Inspect raw assertion
Field
container
Value
Deserialization of Untrusted Data
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Ajax.NET Professional Deserialization of Untrusted Data Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Ajax.NET Professional Deserialization of Untrusted Data Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

83.63% probability · 99.67th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.836330000000; percentile 0.996660000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
1Underlying assertions
1Canonical products
1Target assertions
0Constraint assertions

Grouped from 1 configuration nodes in this exact snapshot. Visual grouping is navigational; asset exposure and root cause require cited evidence.

Identity source boundaries
  • Cpe dictionary1,775,266 records · observed through 2026-07-21T06:45:29.809Z27d65b0f-b718-4b4f-bb79-c47c68d09dfa
  • Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z955dae73-7302-438b-aee1-058d7cc5d48e

2 scope groups

snyk · source assertedn/aAjaxPro.2Direct source scope
Affected: 0 to before unspecified (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "0", "lessThan": "unspecified", "versionType": "custom"}]
NVD CPE · APPLICATIONajaxpro.2_projectajaxpro.2Vulnerable target · 1 assertions
Any version (unconstrained) (< 21.10.30.1)Canonical identity product-78625ff95a682a45c14bda102e8e27f7bea7d3e50b0998406a8578f7614425b5Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:ajaxpro.2_project:ajaxpro.2:*:*:*:*:*:.net:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through excluding 21.10.30.1
    Match ID
    157ccf3c-3a1f-4e28-8650-ff0bcb04835f

Affected-product evidence

Accepted scope and product mapping

0 canonical links · 2 source-reported links

Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Direct cve affected
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
c78a0a06-eeb8-4261-9f30-7abb9826d32b
Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
02f9fd09-071f-41ea-814b-736963a953d7abcbe192-6460-439c-9f1e-3245aaf0f50c

Assessments

CVSS by origin

9.8
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:N/AC:L/Au:N/C:P/I:P/A:P
8.1
report@snyk.ioCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1
snykCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Direct CVE/CNA normalized decisions

8.1Priority eligible

snyk

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Validation
Valid match
Recomputed
8.1
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1

Assessments are retained side by side under closed precedence. Cascade never averages CVSS.

Evidence boundaries

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; remaining scope stays source-scoped.
  • NVD-carried upstream facts remain derivative; independent corroboration requires a separately authored source.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.
  • OSV aggregation and OSV-converted NVD material are not independent corroboration.
  • Red Hat facts are vendor assertions for the exact supplied products.
  • Nonmembership and not-yet-observed states are not proof of safety.