What is CVE-2026-21579?

CVE-2026-21579 is This High severity Information Disclosure vulnerability was introduced in versions 7.17.0, 7.19.0, 8.5.0, 8.9.0, 9.0.1, 9.1.0, 9.2.0…. The supplied enrichment data classifies it as Info Disclosure mapped to CWE-200 Exposure of Sensitive Information.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-21579. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-21579 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-21579. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-21579 using CVSS 7.5, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Prioritize based on EPSS, PoC availability, and external exposure. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

highInfo Disclosure

CVE-2026-21579

CVE-2026-21579 — This High severity Information Disclosure vulnerability was introduced in versions 7.17.0, 7.19.0, 8.5.0, 8.9.0, 9.0.1, 9.1.0, 9.2.0…

This High severity Information Disclosure vulnerability was introduced in versions 7.17.0, 7.19.0, 8.5.0, 8.9.0, 9.0.1, 9.1.0, 9.2.0, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center. This Information Disclosure vulnerability, with a CVSS Score of 8.2, allows an unauthenticated attacker to view sensitive information via an Information Disclosure vulnerability. Atlassian recommends that Confluence Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions: Confluence Data Center 9.2: Upgrade to a release greater than or equal to 9.2.22 Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.14 See the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center from the download center ([https://www.atlassian.com/software/confluence/download-archives]). This vulnerability was reported via our Atlassian (Internal) program.

Published Jul 21, 2026Updated Aug 11, 2026Sources: NVD, Atlassian (CNA)

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

chance of exploitation in 30 days

Affects

Atlassian

11 products listed

CVSS base

7.5

high · 2 sources

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade Confluence Data Center to a fixed release (10.2.14). Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Prioritize based on EPSS, PoC availability, and external exposure.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Atlassian	Confluence Data Center	10.2.0 to 10.2.13	Vulnerable
Atlassian	Confluence Data Center	10.1.0 to 10.1.2	Vulnerable
Atlassian	Confluence Data Center	10.0.2 to 10.0.3	Vulnerable
Atlassian	Confluence Data Center	9.2.0 to 9.2.21	Vulnerable
Atlassian	Confluence Data Center	9.1.0 to 9.1.1	Vulnerable
Atlassian	Confluence Data Center	9.0.1 to 9.0.3	Vulnerable
Atlassian	Confluence Data Center	8.9.5 to 8.9.8	Vulnerable
Atlassian	Confluence Data Center	8.5.14 to 8.5.31	Vulnerable
Atlassian	Confluence Data Center	7.19.26 to 7.19.30	Vulnerable
Atlassian	Confluence Data Center	10.2.14	Patched
Atlassian	Confluence Data Center	9.2.22	Patched

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

None

Confidentiality

High

Integrity

None

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
7.5	CVSS 3.1	high	3.9	3.6	NVD
8.2	CVSS 4.0	high	—	—	Atlassian (CNA)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Weakness & attack patterns

CWE-200Exposure of Sensitive Information

Inferred from the weakness class — not observed against this CVE.

CAPEC-116 · ExcavationCAPEC-118 · Collect and Analyze Information

T1562.003Impair Defenses: Impair Command History Logging
T1574.006Hijack Execution Flow: Dynamic Linker Hijacking
T1574.007Hijack Execution Flow: Path Interception by PATH Environment Variable

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching //confluence.atlassian.com/doc/confluence-release-notes-327.html]), //www.atlassian.com/software/confluence/download-archives]).
Prioritize edge telemetry for network-reachable Confluence Data Center.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 7.5 (AV:N)
Aug 11, 2026 · NVD
Initial · CVE published
Jul 21, 2026 · NVD

References

2 on the record

confluence.atlassian.com/pages/viewpage.action?pageId=1821999345
Vendor Advisory
jira.atlassian.com/browse/CONFSERVER-104340
Issue Tracking

Elsewhere on this site

Atlassianevery CVE for this vendor
Info Disclosuresame class
CWE-200other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-21579 is This High severity Information Disclosure vulnerability was introduced in versions 7.17.0, 7.19.0, 8.5.0, 8.9.0, 9.0.1, 9.1.0, 9.2.0…, a high vulnerability affecting Confluence Data Center from Atlassian. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-21579. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-21579. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 7.5 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.