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CVE Record

CVE-2021-38157: LeoStream Connection Broker 9.x before 9.0.34.3 allows Unauthenticated Reflected XSS via the /index.pl user...

LeoStream Connection Broker 9.x before 9.0.34.3 allows Unauthenticated Reflected XSS via the /index.pl user parameter. NOTE: This vulnerability only affects products that are no longer supported by the maintainer

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-38157 is an unauthenticated reflected cross-site scripting issue in LeoStream Connection Broker 9.x before 9.0.34.3. An attacker could cause malicious script to run in a user’s browser if the user follows a crafted link. The CVE notes the affected products are no longer supported by the maintainer.

Executive priority

Treat this as a cleanup and exposure-reduction item unless an affected broker is internet-facing or business-critical. Unsupported software raises operational risk because normal vendor fixes and support may not be available.

Technical view

The CVE describes reflected XSS in the /index.pl user parameter of LeoStream Connection Broker 9.x before 9.0.34.3. The bundle provides no CVSS, CWE, or detailed affected CPE data. It is not marked as CISA KEV, and the provided evidence does not establish exploitation in the wild.

Likely exposure

Exposure is likely limited to organizations still running unsupported LeoStream Connection Broker 9.x versions before 9.0.34.3, especially where the broker web interface is reachable by users or external networks.

Exploitation context

The issue is unauthenticated and public researcher material is referenced, but the provided sources do not show active exploitation. Reflected XSS generally requires user interaction, such as visiting a crafted URL, and can support phishing or browser-session abuse.

Researcher notes

Key gaps are missing CVSS, CWE, structured CPE data, and vendor remediation detail in the provided bundle. The version boundary before 9.0.34.3 is stated, but current support status should be verified against Leostream lifecycle guidance.

Mitigation direction

  • Inventory LeoStream Connection Broker deployments and identify any 9.x versions before 9.0.34.3.
  • Check current Leostream lifecycle and vendor guidance for supported upgrade or migration paths.
  • Retire unsupported instances where feasible, especially internet-facing broker portals.
  • Restrict access to broker web interfaces to trusted networks and administrative users.
  • Monitor logs and user reports for suspicious links targeting /index.pl parameters.

Validation and detection

  • Confirm product name and exact version from administrative records or asset inventory.
  • Verify whether any Connection Broker web interface is reachable from untrusted networks.
  • Review vendor lifecycle information to determine whether the installed version is unsupported.
  • Check web access logs for unusual /index.pl requests containing user parameter content.
  • Confirm compensating controls, such as access restrictions, are enforced on exposed portals.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-38157 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
5Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.