Security readout for executives and security teams
Plain-English summary
This flaw affects certain libcurl versions on Windows CE when using the Schannel TLS backend. A remote attacker in a man-in-the-middle position could make certificate validation accept an improper wildcard certificate, undermining HTTPS trust for affected clients.
Executive priority
Treat this as high priority for legacy Windows CE or embedded environments that rely on HTTPS for sensitive traffic. It is less urgent for systems without the specific libcurl, Windows CE, and Schannel combination.
Technical view
The issue is in libcurl's Schannel certificate verification path for Windows CE builds, affecting libcurl 7.30.0 through 7.51.0. It is classified as CWE-295 and could allow misvalidation of crafted wildcard SAN certificates, enabling confidentiality, integrity, and availability impact in intercepted TLS sessions.
Likely exposure
Exposure appears narrow: applications must embed or use affected libcurl versions, run on Windows CE, and use the Schannel TLS backend. General libcurl deployments outside that build/runtime combination are not shown as affected by the provided sources.
Exploitation context
The sources describe remote man-in-the-middle risk through crafted certificate subject alternative names. The CVE is not listed as KEV in the provided bundle, so there is no source-supported evidence here of active exploitation.
Researcher notes
The key scope constraint is platform and backend specific: Windows CE with Schannel. The affected version range and upstream patch are identified, but the supplied data does not list downstream products, exploitation in the wild, or compensating controls beyond remediation guidance.
Mitigation direction
- Identify products or firmware using libcurl 7.30.0 through 7.51.0 on Windows CE.
- Apply the curl project patch or move affected builds out of the vulnerable version range.
- Prioritize vendor-supplied updates for embedded or third-party appliances using bundled libcurl.
- If immediate patching is unavailable, reduce exposure to untrusted networks where TLS interception is plausible.
Validation and detection
- Inventory Windows CE applications and firmware for embedded libcurl versions and TLS backend configuration.
- Confirm whether Schannel is used as the TLS backend in affected Windows CE builds.
- Review vendor advisories or SBOMs for libcurl 7.30.0 through 7.51.0 references.
- After remediation, verify the deployed libcurl version or vendor build includes the certificate validation fix.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-295: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2016-9952 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://curl.haxx.se/docs/adv_20161221B.htmlCVE reference · x_refsource_CONFIRM
- https://curl.haxx.se/CVE-2016-9952.patchCVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Certificate Validation
Improper Certificate Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.