Authentication bypass via mismatched GSS connection reuse
Published Mar 30, 2023 · Updated Feb 14, 2025
Authentication bypass in curl libcurl 7.22.0 through 7.88.1 allows remote attackers to reuse a connection with unintended permissions. ConnectionExists omits CURLOPT_GSSAPI_DELEGATION from pooled-connection matching, so a later transfer can inherit the earlier connection's delegation state. Exposure requires connection reuse across krb5, Kerberos, Negotiate, or GSSAPI transfers after the option changes, allowing unauthorized access to data available under the inherited permissions.
Summary
What happened
Authentication bypass in curl libcurl 7.22.0 through 7.88.1 allows remote attackers to reuse a connection with unintended permissions. ConnectionExists omits CURLOPT_GSSAPI_DELEGATION from pooled-connection matching, so a later transfer can inherit the earlier connection's delegation state. Exposure requires connection reuse across krb5, Kerberos, Negotiate, or GSSAPI transfers after the option changes, allowing unauthorized access to data available under the inherited permissions.
The record
- CVE
- CVE-2023-27536
- Published
- Mar 30, 2023
- Updated
- Feb 14, 2025
- Vendor
- curl
- Product
- libcurl
- Classifications
- CWE-287, CWE-305
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 30, 2023CVE publishedPublication date reported by the CVE source.
- Feb 14, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Fixed in 8.0.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GSS delegation too eager connection reuse reportproof of concept · unverified
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Technologies
Your stack
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Your stack
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