Bamboo Data Center: Improper Neutralization of Special Elements used in an OS Command
CVE-2026-21571 is a high-severity improper neutralization of special elements used in an OS command vulnerability in Bamboo Data Center from Atlassian, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Bamboo Data Center versions: 12.1.0 to 12.1.3; 12.0.0 to 12.0.2; 11.0.0 to 11.0.8, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.34% chance of exploitation within 30 days, higher than 72% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Bamboo to 9.6.25 or 10.2.18 or 12.1.6, whichever matches your release line, or a later version.
- Read the advisory on confluence.atlassian.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Atlassian | Bamboo Data Center | 12.1.0 to 12.1.3; 12.0.0 to 12.0.2; 11.0.0 to 11.0.8; 10.2.0 to 10.2.16; 10.1.0 to 10.1.1; 10.0.0 to 10.0.3; 9.6.2 to 9.6.24 | Not stated |
| Atlassian | Bamboo | 9.6.2 up to, but not including, 9.6.25; 10.0.0 up to, but not including, 10.2.18; 11.0.0 up to, but not including, 12.1.6 | 9.6.25, 10.2.18, 12.1.6 |
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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.4 | Critical | CNA (atlassian.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
This Critical severity OS Command Injection vulnerability was introduced in versions 9.6.0, 10.0.0, 10.1.0, 10.2.0, 11.0.0, 11.1.0, 12.0.0, and 12.1.0 of Bamboo Data Center. This RCE (Remote Code Execution) vulnerability, with a CVSS Score of 9.4 and a CVSS Vector of CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H allows an authenticated attacker to execute commands on the remote system, which has high impact to confidentiality, high impact to integrity, high impact to availability, and requires no user interaction. Atlassian recommends that Bamboo 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: Bamboo Data Center 9.6.0: Upgrade to a release greater than or equal to 9.6.25 Bamboo Data Center 10.2: Upgrade to a release greater than or equal to 10.2.18 Bamboo Data Center 12.1: Upgrade to a release greater than or equal to 12.1.6 See the release notes ([https://confluence.atlassian.com/bambooreleases/bamboo-release-notes-1189793869.html]). You can download the latest version of Bamboo Data Center from the download center ([https://www.atlassian.com/software/bamboo/download-archives]).
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in an OS Command
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
- 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.
More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Bamboo Data Center
- 7.5 High severity
- 8.1 High severity
- 8.8 High severity
- 8.0 High severity
- 8.1 High severity
- 8.8 High severity
Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities
- 9.9 Critical severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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