Exploited CVEs / Adobe / CVE-2023-26359

CVE-2023-26359

Adobe ColdFusion Deserialization of Untrusted Data Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2023-09-11 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Adobe Security Bulletins, linked below.

Risk summary

CriticalCISA KEV

9.8

CVSS base

18%

EPSS exploit probability

Critical

Severity

2023-08-21

Added to KEV

2023-09-11 (past due)

CISA due date

Actively exploited Adobe ColdFusion vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2023-08-21.

Senserva AI read on CVE-2023-26359 CISA required action Official fix for CVE-2023-26359 Admin questions

Senserva AI Opinion for CVE-2023-26359

Adobe ColdFusion's deserialization of untrusted data yields code execution in the context of the current user, rated Critical (CVSS 9.8) and confirmed exploited by CISA in August 2023. ColdFusion powers a long tail of legacy government and enterprise web applications that outlived their maintenance budgets, which is precisely the population least likely to have patched. The 18% EPSS score understates the risk to those aging, internet-facing installs.

Do this: Apply Adobe's ColdFusion updates and lockdown guidance, and audit any instance that cannot be patched for isolation or retirement.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2023-26359

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2023-26359, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2023-26359.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2023-26359: Adobe ColdFusion Deserialization of Untrusted Data Vulnerability
- Affected: Adobe ColdFusion
- Severity: Critical, CVSS 9.8; EPSS 30-day exploitation probability 18%
- Added to CISA KEV: 2023-08-21; federal remediation due 2023-09-11
- Ransomware-linked: no
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch now

Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.

The fix ships from the vendor: Adobe Security Bulletins.

Do this now: Federal remediation deadline 2023-09-11; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated August 14, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2023-26359

Published: 2023-08-21
Last revised: 2023-08-21
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

2023-08-21 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 9.8; EPSS first scored at 17.9%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2023-09-11 (past due).

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Official fix for CVE-2023-26359

The authoritative fix and affected-version list are published by the vendor. Find the ColdFusion advisory on Adobe Security Bulletins.

Adobe Security Bulletins CISA KEV entry

Common questions about CVE-2023-26359

Is CVE-2023-26359 actively exploited?

Yes. CVE-2023-26359 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2023-08-21, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 18%.

What is the CISA deadline and required action for CVE-2023-26359?

CISA set the federal (BOD 22-01) remediation due date at 2023-09-11, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

What fixes CVE-2023-26359?

The authoritative fix is in the vendor advisory: see Adobe Security Bulletins for the patched ColdFusion versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2023-26359?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2023-26359's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).

Scope and sources

More exploited Adobe CVEs: CVE-2026-48282 CVE-2009-3459 CVE-2020-9715 CVE-2026-34621 CVE-2025-54236 CVE-2025-54253 CVE-2017-3066 CVE-2024-20767
All Adobe exploited CVEs on one page: Adobe vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.