Review reviewHigh

CVE-2026-45541

espressif esp-idf

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In versions 5.2.6, 5.3.5, 5.4.4, 5.5.4, and 6.0, a NULL-pointer dereference exists in the WebSocket subprotocol-negotiation path of the esp_http_server component. While parsing the client-supplied Sec-WebSocket-Protocol request header during the WebSocket handshake, the tokenisation result is dereferenced without a NULL check, so a malformed header value can crash the server before any application-level authentication runs. This issue has been patched in versions 5.2.7, 5.3.6, 5.4.5, 5.5.5, and 6.0.1.

CVSS: 7.5
EPSS: 0.44%
CISA KEV: Not listed
Published: 2026.06.10

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.44%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: espressif esp-idf
Affected versions: >= = 6.0, >= = 5.5.4, >= = 5.4.4, >= = 5.3.5, >= = 5.2.6, 5.2.6, 5.3.5, 5.4.4, 5.5.4, 6.0
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that espressif esp-idf and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-476