Vulnerability details
CVE-2026-47138
Parse Server: Pre-authentication denial of service via client version header regex backtracking
Official description
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.77 and 9.9.1-alpha.1, an unauthenticated attacker who knows a publicly-known Parse Application ID can submit a single HTTP request whose client SDK version field contains adversarial input that triggers polynomial backtracking in a request-header parser. The parsing runs before session authentication and before rate limiting on every /parse/* request, so the request consumes seconds to minutes of synchronous CPU on a Node.js worker before any access control evaluates it. A small number of concurrent requests can saturate a worker; a single large request via the body-field variant can pin a worker for minutes. Production deployments running the default configuration are affected. This issue has been patched in versions 8.6.77 and 9.9.1-alpha.1.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 8.7High | 4.0 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| parse-community | parse-server | < 8.6.77 | CVEProject cvelistV5 (CNA) |
| parse-community | parse-server | >= 9.0.0, < 9.9.1-alpha.1 | CVEProject cvelistV5 (CNA) |
References and advisories
3- https://github.com/parse-community/parse-server/security/advisories/GHSA-38m6-82c8-4xfm x_refsource_CONFIRM
- https://github.com/parse-community/parse-server/pull/10463 x_refsource_MISC
- https://github.com/parse-community/parse-server/pull/10464 x_refsource_MISC
Details
- Published
- 2026-06-12
- Last updated
- 2026-06-12
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-1333Inefficient Regular Expression Complexity