Security readout for executives and security teams
Plain-English summary
AjaxPro.2 can process attacker-controlled data as arbitrary .NET objects. In a successful attack, an unauthenticated remote actor could execute code, potentially compromising application data, system integrity, and availability. Exploitation is considered more complex, but CISA lists the vulnerability as known exploited.
Executive priority
Treat confirmed exposed deployments as an immediate remediation and threat-hunting priority. CISA KEV status materially raises urgency despite the vulnerability's high-complexity rating. Establish ownership, exposure status, remediation timing, and evidence of compromise review; isolated or unreachable installations can follow risk-based scheduling after validation.
Technical view
CVE-2021-23758 is CWE-502 deserialization of untrusted data in AjaxPro.2. The supplied record states all package versions are vulnerable because arbitrary .NET classes may be deserialized, enabling remote code execution. CVSS 3.1 is 8.1: network-accessible, unauthenticated, no user interaction, high complexity, with high confidentiality, integrity, and availability impact.
Likely exposure
Prioritize internet-accessible .NET applications containing AjaxPro.2, especially where AjaxPro request-handling functionality is reachable. The source bundle describes all versions as affected, although its structured affected-version entry is ambiguous. Confirm deployed packages and exposure directly rather than relying only on version scanners.
Exploitation context
CISA KEV inclusion supports real-world exploitation. The referenced Cisco Talos advisory associates this CVE with UAT-10147 activity. The supplied evidence does not establish exploitation prevalence, specific targets, or whether every deployment configuration is practically exploitable. High attack complexity may constrain exploitation but does not offset confirmed abuse.
Researcher notes
The source bundle supports unauthenticated network attack potential, arbitrary .NET class deserialization, and possible remote code execution. It does not provide safe configuration exceptions or complete patch-version information. The affected-version metadata conflicts with the narrative claim of all versions, so validate package history and the referenced upstream commit before declaring remediation complete.
Mitigation direction
- Identify and prioritize all applications containing AjaxPro.2, beginning with internet-facing systems.
- Consult the upstream commit and current vendor or maintainer guidance for the supported remediation.
- Restrict external access to affected functionality until remediation and validation are complete.
- Apply compensating network controls where immediate package remediation is unavailable.
- Increase monitoring for unusual requests and post-compromise activity on affected servers.
Validation and detection
- Search software inventories, build manifests, and deployed application files for AjaxPro.2.
- Confirm whether AjaxPro request handlers are reachable from untrusted networks without authentication.
- Verify remediation against the referenced upstream change and current maintainer guidance.
- Review relevant server, application, and security logs for suspicious activity.
- Use CISA and Talos reporting to guide incident-review scope and current indicators.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. 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.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-23758 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
CISA KEV status
SSVC decision data
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9snykVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2021-23758 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-08-26T00:00:00.000Z: CVE-2021-23758 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- https://snyk.io/vuln/SNYK-DOTNET-AJAXPRO2-1925971CVE reference, snyk
- https://github.com/michaelschwarz/Ajax.NET-Professional/commit/b0e63be5f0bb20dfce507cb8a1a9568f6e73de57CVE reference, snyk
- https://blog.talosintelligence.com/uat-10147-chinese-speaking-adversary-integrates-agentic-ai-into-post-compromise-operations/CVE reference, CISA-ADP · third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-23758CVE reference, CISA-ADP · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.