Cleartext transfer via isolated parallel HSTS caches
Published Feb 23, 2023 · Updated Feb 13, 2026
Cleartext transmission in curl 7.77.0 through 7.87.0 allows man-in-the-middle attackers to intercept a later HTTP transfer. Parallel transfers maintain separate HSTS state, and the last completed transfer overwrites the cache file without entries learned by other transfers. The command-line tool must use --hsts with --parallel and later request an affected host over HTTP; libcurl is not affected.
Summary
What happened
Cleartext transmission in curl 7.77.0 through 7.87.0 allows man-in-the-middle attackers to intercept a later HTTP transfer. Parallel transfers maintain separate HSTS state, and the last completed transfer overwrites the cache file without entries learned by other transfers. The command-line tool must use --hsts with --parallel and later request an affected host over HTTP; libcurl is not affected.
The record
- CVE
- CVE-2023-23915
- Published
- Feb 23, 2023
- Updated
- Feb 13, 2026
- Vendor
- curl
- Product
- curl
- Classifications
- CWE-319, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 23, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Fixed in 7.88.0
What conditions does exploitation require?
What is affected?
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
- Upstream HSTS amnesia reproductionproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo