Vulnerability in Go Standard Library Net/http/internal

CVE-2025-22871

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.008 (55.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-22871: held from 0.008 to 0.008.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: +0.000

Affected products

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-22871?
CVE-2025-22871 is a critical-severity vulnerability in Go Standard Library Net/http/internal, classified under CWE-444: INCONSISTENT INTERPRETATION OF HTTP REQUESTS ('HTTP REQUEST SMUGGLING'). CVSS score: 9.1/10. Published 2025-04-08.
How severe is CVE-2025-22871?
Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2025-22871 known to be exploited?
10 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.