CVE-2026-21577

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 85% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 4 sources updated this week
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

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

This High severity DoS (Denial of Service) vulnerability was introduced in versions 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0 and 10.2.0 of Confluence Data Center. This DoS (Denial of Service) vulnerability, with a CVSS Score of 7.1, allows an authenticated attacker to cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network. 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 9.2.17 Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.7 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 Penetration Testing program.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
32(Track)
EG Risk 32/100SSVC: 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
Severity71% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
14%
KEV
Not listed

Published

July 21, 2026

Last Modified

July 22, 2026

Advisory Details (2)

Auto-updated Jul 21, 2026
No patch confirmed yet.
generic

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https://jira.atlassian.com/browse/CONFSERVER-104334
generic

Security Bulletin - July 21 2026 | Atlassian Support | Atlassian Documentation

https://confluence.atlassian.com/pages/viewpage.action?pageId=1821999345

Vendor Advisories for CVE-2026-21577(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 21× 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. 2026-07-27 14:13 UTCEPSS rescore
  2. 2026-07-27 12:59 UTCGHSA enrichment
  3. 2026-07-26 23:42 UTCEG score recompute
  4. 2026-07-26 23:42 UTCGHSA enrichment
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 14:54 UTCEPSS rescore
  7. 2026-07-26 10:30 UTCEG score recompute
  8. 2026-07-26 10:30 UTCGHSA enrichment
  9. 2026-07-25 14:17 UTCEPSS rescore
  10. 2026-07-25 14:17 UTCEPSS rescore
  11. 2026-07-24 14:17 UTCEPSS rescore
  12. 2026-07-23 14:18 UTCEPSS rescore
  13. 2026-07-23 14:18 UTCEPSS rescore
  14. 2026-07-23 03:06 UTCEG score recompute
  15. 2026-07-22 23:04 UTCEG score recompute
  16. 2026-07-22 23:04 UTCGHSA enrichment
  17. 2026-07-22 14:08 UTCEPSS rescore
  18. 2026-07-21 20:08 UTCEG score recompute
  19. 2026-07-21 20:08 UTCGHSA enrichment
  20. 2026-07-21 17:40 UTCEG score recompute
  21. 2026-07-21 17:38 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-21577?
CVE-2026-21577 is a high vulnerability published on July 21, 2026. This High severity DoS (Denial of Service) vulnerability was introduced in versions 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0 and 10.2.0 of Confluence Data Center. This DoS (Denial of Service) vulnerability, with a CVSS Score of 7.1, allows an authenticated attacker to cause a…
When was CVE-2026-21577 disclosed?
CVE-2026-21577 was first published in the National Vulnerability Database on July 21, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-21577 actively exploited?
CVE-2026-21577 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 85.5% of all scored CVEs.
What is the CVSS score of CVE-2026-21577?
CVE-2026-21577 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-21577?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-21577, 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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