Strix
26.1K

CVE-2026-23527

CRITICALCVSS 9.8/10EPSS 0.58%

Last modified

CVE-2026-23527 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. H3 is a minimal H(TTP) framework built for high performance and portability. Prior to 1.15.5, there is a critical HTTP Request Smuggling vulnerability. EPSS estimates a 0.58% chance of exploitation in the next 30 days.

Description

H3 is a minimal H(TTP) framework built for high performance and portability. Prior to 1.15.5, there is a critical HTTP Request Smuggling vulnerability. readRawBody is doing a strict case-sensitive check for the Transfer-Encoding header. It explicitly looks for "chunked", but per the RFC, this header should be case-insensitive. This vulnerability is fixed in 1.15.5.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.58%

43.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
H3H3< 1.15.5

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-23527?
H3 is a minimal H(TTP) framework built for high performance and portability. Prior to 1.15.5, there is a critical HTTP Request Smuggling vulnerability. readRawBody is doing a strict case-sensitive check for the Transfer-Encoding header. It explicitly looks for "chunked", but per the RFC, this header should be case-insensitive. This vulnerability is fixed in 1.15.5.
How severe is CVE-2026-23527?
CVE-2026-23527 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.58% probability of exploitation in the next 30 days.
How do I fix CVE-2026-23527?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-23527?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST