Cookie attribute override via unescaped options
Published Sep 10, 2026 · Updated Sep 10, 2026
Set-Cookie attribute injection in cookies before 0.9.2 allows remote attackers to override cookie security attributes with crafted option data. The cookie serialization path validates domain and path with an RFC 7230 field-content matcher that accepts semicolons, then appends both values unescaped to the Set-Cookie header. Exploitation requires an application to pass untrusted or request-derived data into either option; injected attributes can weaken SameSite, Secure, HttpOnly, or Domain restrictions.
Summary
What happened
Set-Cookie attribute injection in cookies before 0.9.2 allows remote attackers to override cookie security attributes with crafted option data. The cookie serialization path validates domain and path with an RFC 7230 field-content matcher that accepts semicolons, then appends both values unescaped to the Set-Cookie header. Exploitation requires an application to pass untrusted or request-derived data into either option; injected attributes can weaken SameSite, Secure, HttpOnly, or Domain restrictions.
The record
- CVE
- CVE-2026-88038
- Published
- Sep 10, 2026
- Updated
- Sep 10, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-74
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 10, 2026CVE publishedPublication date reported by the CVE source.
- Sep 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
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Technologies
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