7.5

CVE-2018-1000520: arm mbed_tls Improper Certificate Validation

CVSS: 7.5v3.0HighModified
AliasesUBUNTU-CVE-2018-1000520DEBIAN-CVE-2018-1000520
Published 26-06-2018Last modified 05-08-2024
Open JSON

Vulnerability summary

CVE-2018-1000520 is a high (CVSS 7.5) Improper Certificate Validation vulnerability in arm mbed_tls. EPSS estimates a 0.80% chance of exploitation in the next 30 days, higher than 55.7% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.0 (NVD)
EPSS score
0.80%
0%100%
Low · +0.09 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 26-06-2018
    PublishedVulnerability first disclosed.
  2. 05-08-2024
    Last modifiedVulnerability information updated.

Description

ARM mbedTLS version 2.7.0 and earlier contains a Ciphersuite Allows Incorrectly Signed Certificates vulnerability in mbedtls_ssl_get_verify_result() that can result in ECDSA-signed certificates are accepted, when only RSA-signed ones should be.. This attack appear to be exploitable via Peers negotiate a TLS-ECDH-RSA-* ciphersuite. Any of the peers can then provide an ECDSA-signed certificate, when only an RSA-signed one should be accepted..

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.80%

Chance of exploitation in the next 30 days

Percentile

56%

Versus all other CVEs

30-day change

+0.09 pp

From 0.71% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.80%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Arm1 product
Debian1 product
  • mbedtlsAll versions (No fix recorded)
Ubuntu1 product
  • mbedtlsAll versions (No fix recorded)

3 vendors · 3 products

References

4 links