Is there a public exploit for CVE-2026-82391?

No public exploit for CVE-2026-82391 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-82391?

CVE-2026-82391 scores CVSS 9.1 (v3.1), rated critical.

What does CVE-2026-82391 affect?

CVE-2026-82391 affects zephyrproject Zephyr.

9.1 Critical

The HTTP/2 front-end of the Zephyr HTTP server aliased connection receive state as a scratch output.

CVE-2026-82391

The HTTP/2 front-end of the Zephyr HTTP server aliased connection receive state as a scratch output. In subsys/net/lib/http/httpserverhttp2.c, handlehttp2staticfsresource() passed &client->datalen as the filesize out-parameter of httpserverfindfile(). client->datalen is the count of unprocessed bytes remaining in the fixed-size per-connection receive buffer client->buffer[CONFIGHTTPSERVERCLIENTBUFFERSIZE] (256 bytes by default), an invariant every frame handler and the socket receive path rely on. Serving any static file therefore replaced that bounded value with the file's on-disk size, and nothing resets it afterwards. The defect is reached by an unauthenticated HTTP/2 GET for any file under the web root, in applications that register a static-filesystem resource (HTTPRESOURCETYPESTATICFS) with CONFIGFILESYSTEM=y; CONFIGHTTPSERVERVERSION2 is enabled by default and no TLS or credentials are required on this path. Once client->datalen exceeds the buffer size, the frame dispatch loop in subsys/net/lib/http/httpservercore.c keeps parsing past the end of the received data, and the peer controls the bytes at client->cursor, so it can choose which fabricated frame the state machine…

Assessment

CVSS: 9.1 (v3.1)
Severity: Critical
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 10 November 2026
Last updated: 10 November 2026
Affected: zephyrproject · Zephyr
Assigner: zephyr

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

At the source

EUVD (ENISA)

References

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