CVE-2023-38203
CVE-2023-38203 is a security flaw in Adobe ColdFusion, Adobe’s platform for building web applications. Attackers can run their own code on Adobe ColdFusion. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 8 Jan 2024, and says ransomware gangs have used it.[1]
Adobe ColdFusion is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Adobe has published a fix or advice.
Description
CISA calls it a deserialization of untrusted data in Adobe ColdFusion. In its words: “Adobe ColdFusion contains a deserialization of untrusted data vulnerability that allows for code execution.”[1]
The CVE record adds: “Adobe ColdFusion versions 2018u17 (and earlier), 2021u7 (and earlier) and 2023u1 (and earlier) are affected by a Deserialization of Untrusted Data vulnerability that could result in Arbitrary code execution. Exploitation of this issue does not require user interaction.”[2]
The underlying weakness is deserialization of untrusted data (CWE-502), in MITRE’s list of common software weaknesses.
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Adobe’s advisory has them[3]. CISA names the product as Adobe ColdFusion.
Most families won’t have Adobe ColdFusion; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 8 Jan 2024, 172 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 29 Jan 2024 to fix it.[1] CISA says ransomware gangs have used it.
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 97%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Adobe has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.Adobe ColdFusion is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 29 Jan 2024 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 97%.[4] |
See also
Other Adobe ColdFusion flaws
- CVE-2026-48282: path traversal ·
- CVE-2017-3066: deserialization ·
- CVE-2024-20767: improper access control ·
- CVE-2023-29300: deserialization of untrusted data ·
- CVE-2023-26359: deserialization of untrusted data ·
- CVE-2023-38205: improper access control ·
Other Adobe flaws
- CVE-2026-48356, Adobe Commerce and Magento: unrestricted upload of file with dangerous type ·
- CVE-2026-71362, Adobe Commerce and Magento: incorrect authorization ·
- CVE-2026-75650, Adobe Commerce and Magento: improper neutralization of special elements used in a template engine ·
- CVE-2009-3459, Adobe Acrobat and Reader: heap-based buffer overflow ·
- CVE-2026-34621, Adobe Acrobat and Reader: prototype pollution ·
Other deserialization of untrusted data flaws
- CVE-2021-23758, Ajax.NET Professional: deserialization of untrusted data ·
- CVE-2026-63077, JetBrains TeamCity: deserialization of untrusted data ·
- CVE-2026-50522, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-58644, Microsoft SharePoint: deserialization of untrusted data ·
- CVE-2026-45659, Microsoft SharePoint Server: deserialization of untrusted data ·
Added the same day
- CVE-2023-41990, Apple devices: code execution ·
- CVE-2023-29300, Adobe ColdFusion: deserialization of untrusted data ·
- CVE-2023-27524, Apache Superset: insecure default initialization of resource ·
- CVE-2023-23752, Joomla!: improper access control ·
- CVE-2016-20017, D-Link DSL-2750B Devices: command injection ·
Every Adobe flaw on CISA’s list · Everything added in January 2024
References
- ^ Cybersecurity and Infrastructure Security Agency. “Adobe ColdFusion Deserialization of Untrusted Data Vulnerability”. Known Exploited Vulnerabilities Catalog, added 8 Jan 2024.
- ^ National Institute of Standards and Technology. “CVE-2023-38203 Detail”. National Vulnerability Database, published 20 Jul 2023.
- ^ Adobe. Advisories and fixes: helpx.adobe.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.971, percentile 99.9, 31 Oct 2026.
- CVE Program. “CVE-2023-38203”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.