High severity · published Jun 10, 2026
CVE-2026-45541
ESF-IDF: Remote Null Pointer Dereference in WebSocket Server
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ES
esp-idf · espressif
= 6.0; = 5.5.4; = 5.4.4; = 5.3.5; = 5.2.6 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45541
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45541
Patch
https://github.com/espressif/esp-idf/commit/00a2f7fbbbd8fe6d04729022e1d5c9a49435bfe8
Patch
https://github.com/espressif/esp-idf/commit/0dc4ee7537f3b12350f5966cecacd59bba840ec6
Patch
https://github.com/espressif/esp-idf/commit/37508ab91124ef426a7396d30f79eba1162700c7
Patch
https://github.com/espressif/esp-idf/commit/9fc0ca13b3b85b98d32b98cd9dc8ff9d82642b7b
Patch
https://github.com/espressif/esp-idf/commit/dc46dc51359749e50617eb70d6f9ae298adc4fff
Patch
https://github.com/espressif/esp-idf/commit/f88a47e4f37fb11ae4b0908cd5c80059d83198c6
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