---
title: "CVE-2021-26086: Atlassian Jira Server and Data Center Path Traversal Vulnerability"
url: https://erroneo.us/security/cve/CVE-2021-26086/
description: "CVE-2021-26086 (Atlassian Jira Server and Data Center): Exploited in the wild (CISA KEV). Affected versions of Atlassian Jira Server and Data Center allow…"
type: vulnerability-record
section: "Security Digest"
date_published: 2021-08-16
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2021-26086"
kev: true
cvss: 5.3
epss: 0.99999
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2021-26086: Atlassian Jira Server and Data Center Path Traversal Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Atlassian Jira Server and Data Center. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-11-12, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-12-03 ; treat that as the outer limit, not the target.
- EPSS 100.0% , percentile 100.0: FIRST’s model estimates a 100.0% chance of exploitation activity in the next 30 days, higher than 100.0% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

Affected versions of Atlassian Jira Server and Data Center allow remote attackers to read particular files via a path traversal vulnerability in the /WEB-INF/web.xml endpoint. The affected versions are before version 8.5.14, from version 8.6.0 before 8.13.6, and from version 8.14.0 before 8.16.1.

## Affected products (CVE record)

- Atlassian Jira Server: unspecified < 8.5.14, 8.6.0 < unspecified, unspecified < 8.13.6, 8.14.0 < unspecified, unspecified < 8.16.1
- Atlassian Jira Data Center: unspecified < 8.5.14, 8.6.0 < unspecified, unspecified < 8.13.6, 8.14.0 < unspecified, unspecified < 8.16.1

## Severity

- CISA-ADP CVSS 3.1: 5.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`

## Exploitation

- CISA KEV: added 2024-11-12; federal due date 2024-12-03. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 100.00% probability of exploitation activity in the next 30 days; percentile 100.0.

## Sources

- [Listed in CISA KEV notes (jira.atlassian.com)](https://jira.atlassian.com/browse/JRASERVER-72695)
- [CVE.org record CVE-2021-26086](https://www.cve.org/CVERecord?id=CVE-2021-26086)
- [NVD entry CVE-2021-26086](https://nvd.nist.gov/vuln/detail/CVE-2021-26086)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26086)
- [packetstormsecurity.com](http://packetstormsecurity.com/files/164405/Atlassian-Jira-Server-Data-Center-8.4.0-File-Read.html)

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Source page: https://erroneo.us/security/cve/CVE-2021-26086/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt