Atlassian Jira Server and Data Center Path Traversal
CVE-2021-26086 is a medium-severity improper limitation of a pathname to a restricted directory vulnerability in Jira Server from Atlassian, with a CVSS 3.1 base score of 5.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 8.5.14, 8.13.6, 8.16.1 as the first without the flaw, so updating Jira Server to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on November 12, 2024, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Jira Server to 8.5.14 or 8.13.6 or 8.16.1, whichever matches your release line, or a later version.
- Update Jira Data Center to 8.5.14 or 8.13.6 or 8.16.1, whichever matches your release line, or a later version.
- CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- Read the advisory on jira.atlassian.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Atlassian | Jira Server | before 8.5.14; 8.6.0; before 8.13.6; 8.14.0; before 8.16.1; 8.6.0 up to, but not including, 8.13.6; 8.14.0 up to, but not including, 8.16.1 | 8.5.14, 8.13.6, 8.16.1 |
| Atlassian | Jira Data Center | before 8.5.14; 8.6.0; before 8.13.6; 8.14.0; before 8.16.1; 8.6.0 up to, but not including, 8.13.6; 8.14.0 up to, but not including, 8.16.1 | 8.5.14, 8.13.6, 8.16.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.3 | Medium | NVD |
| CVSS 3.1 | 5.3 | Medium | CISA (ADP) |
| CVSS 2.0 | 5.0 | Medium | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: partial).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
- jira.atlassian.com/browse/JRASERVER-72695Issue Tracking
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26086US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/164405/Atlassian-Jira-Server-Data-Center-8.4.0-File-Read.htmlExploit, Third Party Advisory, VDB Entry
Other vulnerabilities in Jira Server
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