CVE-2021-23758

HIGHNVD 8.19.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because EPSS predicts 89% probability of exploitation within the next 30 days (top 0.2% of all CVEs). NVD baseline CVSS 8.1 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, nvd
Trending — 3 sources updated this weekWeaponized
8.1
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 89%
CISA-KEV: Not listedEPSS: 89%CVSS: 8.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.1
EG Score
9.0(high)
EG Risk
81(Track)
EG Risk 81/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation89% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
99.8%
KEV
Not listed

Published

December 3, 2021

Last Modified

November 21, 2024

References (6)

Affected Packages

(1 across 1 ecosystem)
NuGet(1)
PackageVulnerable rangeFixed inDependents
AjaxNetProfessional21.10.30, 21.11.22, 21.11.2921.11.29.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 21× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 01:57 UTCEG score recompute
  2. 2026-07-22 22:44 UTCEG score recompute
  3. 2026-07-22 14:05 UTCEPSS rescore
  4. 2026-07-20 17:04 UTCEPSS rescore
  5. 2026-07-18 06:59 UTCOSV refresh
  6. 2026-07-16 17:00 UTCEPSS rescore
  7. 2026-07-15 16:55 UTCEPSS rescore
  8. 2026-07-15 16:55 UTCEPSS rescore
  9. 2026-07-13 06:10 UTCEPSS rescore
  10. 2026-07-13 06:10 UTCEPSS rescore
  11. 2026-07-06 02:21 UTCEPSS rescore
  12. 2026-07-06 02:21 UTCEPSS rescore
  13. 2026-06-30 04:30 UTCOSV refresh
  14. 2026-06-28 04:54 UTCEPSS rescore
  15. 2026-06-28 04:54 UTCEPSS rescore
  16. 2026-06-25 13:48 UTCEPSS rescore
  17. 2026-06-25 13:48 UTCEPSS rescore
  18. 2026-06-24 14:03 UTCEPSS rescore
  19. 2026-06-24 14:03 UTCEPSS rescore
  20. 2026-06-23 21:31 UTCEPSS rescore
  21. 2026-06-23 21:31 UTCEPSS rescore
  22. 2026-06-17 17:51 UTCEPSS rescore
  23. 2026-06-15 17:46 UTCEPSS rescore
  24. 2026-06-14 23:15 UTCEPSS rescore
  25. 2026-06-12 23:10 UTCEPSS rescore
Show 23 more
  1. 2026-06-12 23:10 UTCEPSS rescore
  2. 2026-06-12 15:40 UTCOSV refresh
  3. 2026-06-11 13:58 UTCEPSS rescore
  4. 2026-06-10 22:16 UTCEPSS rescore
  5. 2026-06-10 22:16 UTCEPSS rescore
  6. 2026-06-10 13:20 UTCEPSS rescore
  7. 2026-06-08 14:15 UTCEPSS rescore
  8. 2026-06-08 14:15 UTCEPSS rescore
  9. 2026-06-07 15:23 UTCEPSS rescore
  10. 2026-06-07 15:23 UTCEPSS rescore
  11. 2026-06-05 22:45 UTCEPSS rescore
  12. 2026-06-05 22:45 UTCEPSS rescore
  13. 2026-06-05 06:09 UTCEPSS rescore
  14. 2026-06-05 06:09 UTCEPSS rescore
  15. 2026-06-05 06:08 UTCEPSS rescore
  16. 2026-06-04 13:10 UTCEPSS rescore
  17. 2026-06-01 13:50 UTCEPSS rescore
  18. 2026-06-01 13:50 UTCEPSS rescore
  19. 2026-05-29 13:42 UTCEPSS rescore
  20. 2026-05-28 13:43 UTCEPSS rescore
  21. 2026-05-28 13:43 UTCEPSS rescore
  22. 2026-05-27 13:39 UTCEPSS rescore
  23. 2026-05-26 06:55 UTCEG score recompute

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 Metasploit module) (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCnumanturle/CVE-2021-23758-POC
    First seen Dec 15, 2021
    Open source ↗
  • Metasploitexploit/windows/http/ajaxpro_deserialization_rce✓ verified
    First seen Dec 3, 2021

    AjaxPro Deserialization Remote Code Execution

    Open source ↗

Frequently asked(5)

What is CVE-2021-23758?
CVE-2021-23758 is a high vulnerability published on December 3, 2021. 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.
When was CVE-2021-23758 disclosed?
CVE-2021-23758 was first published in the National Vulnerability Database on December 3, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-23758 actively exploited?
CVE-2021-23758 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-23758?
CVE-2021-23758 has a CVSS v3 base score of 8.1 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
How do I remediate CVE-2021-23758?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-23758, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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