CVE-2023-22515
CVE-2023-22515 is a security flaw in Atlassian Confluence Data Center and Server, a wiki companies use for internal documents. Attackers can reach parts of Atlassian Confluence Data Center and Server that should be locked to them. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 5 Oct 2023, and says ransomware gangs have used it.[1]
Atlassian Confluence Data Center and Server 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. Atlassian has published a fix or advice.
Description
CISA calls it a broken access control in Atlassian Confluence Data Center and Server. In its words: “Atlassian Confluence Data Center and Server contains a broken access control vulnerability that allows an attacker to create unauthorized Confluence administrator accounts and access Confluence.”[1]
The CVE record adds: “Atlassian has been made aware of an issue reported by a handful of customers where external attackers may have exploited a previously unknown vulnerability in publicly accessible Confluence Data Center and Server instances to create unauthorized Confluence administrator accounts and access Confluence instances. Atlassian Cloud sites are not affected by this vulnerability. If your Confluence site is accessed via an atlassian.net domain, it is hosted by Atlassian and is not vulnerable to this issue.”[2]
The underlying weakness is improper input validation (CWE-20), 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 NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Atlassian’s advisory has them[3]. CISA names the product as Atlassian Confluence Data Center and Server.
Most families won’t have Atlassian Confluence Data Center and Server; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 5 Oct 2023, within a day of it being made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 13 Oct 2023 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 99%. 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
Atlassian 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.Atlassian Confluence Data Center and Server 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 13 Oct 2023 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 99%.[4] |
See also
Other Atlassian Confluence Data Center and Server flaws
- CVE-2023-22527: template injection ·
- CVE-2023-22518: improper authorization ·
Other Atlassian flaws
- CVE-2026-21589, Atlassian products: files or directories accessible to external parties ·
- CVE-2021-26086, Atlassian Jira Server and Data Center: path traversal ·
- CVE-2022-36804, Atlassian Bitbucket Server and Data Center: command injection ·
- CVE-2022-26138, Atlassian Confluence: questions for confluence app hard-coded credentials ·
- CVE-2022-26134, Atlassian Confluence Server/Data Center: confluence server and data center remote code execution ·
Other improper input validation flaws
- CVE-2026-93952, Arista VeloCloud Orchestrator: improper input validation ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
- CVE-2026-12569, PTC Windchill and FlexPLM: improper input validation ·
- CVE-2026-34910, Ubiquiti UniFi OS: improper input validation ·
- CVE-2026-6973, Ivanti Endpoint Manager Mobile (EPMM): improper input validation ·
Added the same day
- CVE-2023-42824, Apple iOS and iPadOS: kernel privilege escalation ·
- CVE-2023-40044, Progress WS_FTP Server: deserialization of untrusted data ·
Every Atlassian flaw on CISA’s list · Everything added in October 2023
References
- ^ Cybersecurity and Infrastructure Security Agency. “Atlassian Confluence Data Center and Server Broken Access Control Vulnerability”. Known Exploited Vulnerabilities Catalog, added 5 Oct 2023.
- ^ National Institute of Standards and Technology. “CVE-2023-22515 Detail”. National Vulnerability Database, published 4 Oct 2023.
- ^ Atlassian. Advisories and fixes: confluence.atlassian.com, confluence.atlassian.com, confluence.atlassian.com, jira.atlassian.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.992, percentile 99.9, 31 Oct 2026.
- CVE Program. “CVE-2023-22515”. 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.