Certification Validation Issues in libcurl with wolfSSL from curl
CVE-2026-82208

7.5HIGH

Key Information:

Vendor

Curl

Status
Vendor
CVE Published:
6 September 2026

What is CVE-2026-82208?

The libcurl library, when utilizing the wolfSSL backend with CA caching enabled, has a flaw that allows the incorrect acceptance of certificates. A callback function specified via CURLOPT_SSL_CTX_FUNCTION, which is intended to replace the trust store, can inadvertently cause libcurl to reinstall a previously cached certificate store after the callback concludes. This situation can lead to scenarios where a certificate, deemed invalid by the new trust store selected by the callback, may still be allowed due to its presence in the cached store. This vulnerability raises significant concerns about the integrity of certificate validation processes in applications relying on libcurl, particularly those enforcing strict security measures.

Affected Version(s)

curl 8.9.1 < 8.14.2

curl 8.15.0 < 8.16.1

curl 8.17.0 < 8.20.1

References

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Stanislav Fort (Aisle Research)
Stefan Eissing
.