Reflected cross-site scripting in localstack allows script injection
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-79.
Summary
localstack v4.9.2 is affected by a reflected cross-site scripting flaw (CWE-79). Input from a crafted URL is echoed into a web page without proper neutralization. A remote attacker who gets a user to open the crafted URL can run arbitrary JavaScript in that user's browser context, with limited impact on confidentiality and integrity.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
A reflected cross-site scripting (XSS) vulnerability in localstack v4.9.2 allows attackers to execute arbitrary Javascript in the context of the user's browser via a crafted URL.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
The sources list no fixed version for localstack.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Timeline
- 2026-10-22 Threatist record created from CVE-2025-69723
- 2026-10-22 Alias added: GHSA-cq3h-9qqr-9fhq
- 2026-10-26 CVSS score added · CISA ADP
- 2026-10-26 Weakness changed · CISA ADP
- 2026-10-26 CISA SSVC decision points changed
- 2026-10-26 Priority changed: LOW → MEDIUM
References
Sources
- CVE-2025-69723 · CVE Program
- CVE-2025-69723 · NVD
- FIRST EPSS
- GHSA-cq3h-9qqr-9fhq · GitHub Advisory Database · CC BY 4.0
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