Security readout for executives and security teams
Plain-English summary
Some systems using ARM mbedTLS 2.7.0 or earlier may accept a certificate signed with ECDSA even when the negotiated TLS ciphersuite should require RSA. This can weaken certificate trust decisions in affected TLS connections. The public source bundle does not provide CVSS, known exploitation, or a named fixed version.
Executive priority
Treat this as a targeted TLS trust issue, not a broad emergency based on available evidence. Prioritize inventory and remediation for internet-facing or vendor-managed embedded systems using old mbedTLS versions.
Technical view
The CVE describes incorrect certificate signature-type handling in mbedtls_ssl_get_verify_result(). When peers negotiate a TLS-ECDH-RSA-* ciphersuite, an ECDSA-signed certificate may be accepted even though an RSA-signed certificate should be required.
Likely exposure
Exposure is likely limited to products, firmware, or services embedding ARM mbedTLS 2.7.0 or earlier and allowing TLS-ECDH-RSA-* ciphersuite negotiation.
Exploitation context
The CVE is not listed as KEV in the provided bundle. The described condition requires a TLS peer relationship where TLS-ECDH-RSA-* is negotiated and the certificate signature type is mismatched.
Researcher notes
The source bundle names the vulnerable function and negotiation condition, but omits CVSS, CWE, patch details, and exploit evidence. Validation should focus on affected mbedTLS versioning and whether TLS-ECDH-RSA-* ciphersuites are reachable.
Mitigation direction
- Inventory applications, devices, and firmware using ARM mbedTLS 2.7.0 or earlier.
- Check ARM mbedTLS vendor guidance and release notes for the supported fix path.
- Disable TLS-ECDH-RSA-* ciphersuites where feasible and compatible with business requirements.
- Prioritize externally reachable TLS services and embedded products with long update cycles.
Validation and detection
- Confirm deployed mbedTLS versions in binaries, SBOMs, firmware manifests, and vendor attestations.
- Review TLS configurations for enabled TLS-ECDH-RSA-* ciphersuites.
- Verify certificate validation tests reject mismatched certificate signature algorithms.
- Check vendor advisories for fixed versions before closing remediation tickets.
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.
CVE-2018-1000520 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/ARMmbed/mbedtls/issues/1561CVE reference · x_refsource_MISC
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.