What’s Vulnerable › Vulnerabilities

CVE-2025-22871: Request smuggling due to acceptance of invalid chunked data in net/http

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-04-08 · updated 2026-06-17

Description

The net/http package improperly accepts a bare LF as a line terminator in chunked data chunk-size lines. This can permit request smuggling if a net/http server is used in conjunction with a server that incorrectly accepts a bare LF as part of a chunk-ext.

Affected products

• Go standard library net/http/internal: before 1.23.8; from 1.24.0-0 before 1.24.2 — fixed in 1.23.8, 1.24.2

How to fix

Upgrade to a fixed version: Go standard library net/http/internal 1.23.8, 1.24.2. Check the vendor advisory for mitigations.

References

• https://go.dev/cl/652998
• https://go.dev/issue/71988
• https://groups.google.com/g/golang-announce/c/Y2uBTVKjBQk
• https://pkg.go.dev/vuln/GO-2025-3563
• http://www.openwall.com/lists/oss-security/2025/04/04/4
• https://cert-portal.siemens.com/productcert/html/ssa-783943.html

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