CVE-2026-79980
Description détaillée
The DHCPv4 client in subsys/net/lib/dhcpv4/dhcpv4.c maintained its transaction identifier (iface->config.dhcpv4.xid) as a counter rather than as a per-transaction random value. It was seeded once with sys_rand32_get() in dhcpv4_start_internal(), incremented by one in dhcpv4_send_discover() and dhcpv4_send_decline(), and never changed by dhcpv4_send_request() — so every RENEWING and REBINDING exchange reused, unchanged, the identifier that had already appeared on the wire in the broadcast DHCPDISCOVER at boot, and where the identifier did move it moved predictably by one. RFC 2131 4.1 requires a single identifier per transaction, chosen so that clients are unlikely to collide. This identifier is the client's only unpredictable reply-validation token. net_dhcpv4_input() accepts a BOOTP reply on op, a matching xid, and a matching chaddr (the interface MAC, which is public); the UDP callback is registered with a wildcard remote address and port, and no server-identifier or source-address check is applied. An attacker who learns one identifier — for example any host on the same segment that sees the broadcast DHCPDISCOVER, or a DHCP server or relay on a network the device previously joined — therefore retains a valid token for the device's whole uptime, and can predict the identifiers of later exchanges, without having to observe the unicast renew traffic or race the legitimate server. A forged reply that passes those checks has effect regardless of client state, because dhcpv4_parse_options() applies its side effects before the state machine gate in dhcpv4_handle_reply(): the router option calls net_if_ipv4_set_gw() and the DNS option calls dns_resolve_reconfigure(). A single accepted datagram can thus repoint the device's default gateway and resolvers at attacker-controlled addresses, redirecting its traffic; during RENEWING or REBINDING a forged DHCPACK re-binds the lease with attacker-chosen parameters and a forged DHCPNAK removes the address and restarts configuration. The fix draws a fresh sys_rand32_get() value at each point where a transaction begins — entering SELECTING, RENEWING and REBINDING, and at the INIT/INIT-REBOOT entry taken when an interface with a lease goes down — while REQUESTING and DECLINE keep the identifier of the exchange they belong to, as RFC 2131 requires. As a side effect the client also no longer discards a slow server's offer after retransmitting a discover, and the initial-discover backoff now draws its own randomness instead of deriving it from the identifier.
Vecteur d'attaque (CVSS)
Dernières Vulnérabilités
CVE-2026-83813
Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.names.dns.DNSDatagramProtocol accepts a UDP DNS response for a pending query when its 16-bit transaction ID matches but does not verify that the response came from the queried host and port. An attacker able to deliver a packet to the resolver's listening port with the correct transaction ID can inject a forged answer. The standard twisted.names.client.Resolver uses a new random source port for each query, increasing off-path attack complexity, while applications that reuse a DNSDatagramProtocol instance expose only the transaction-ID search space after the first query. A successful forgery can redirect hostname resolution and enable mail interception, server-side request forgery, or man-in-the-middle positioning. This issue is fixed in version 26.10.0rc1.
CVE-2026-75525
OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. In versions 2.1.0 and prior, an unauthenticated attacker can store an arbitrary ML-KEM-768 public key under any existing user's identity in any tenant's staff-crypto recipient directory. The product's design guarantees that appointment data is end-to-end encrypted to staff members and that the staff recipient directory is not attacker-writable, so that even administrators and the operator cannot read patient data. This endpoint breaks that guarantee for an unauthenticated remote actor: it allows writing an arbitrary encryption recipient into the recipient directory of any tenant. The injected key receives the tunnel key of every appointment booked afterward in that tenant, because booking clients encrypt to all active staff keys. The attacker holds the corresponding secret key and is a persistent, unauthorized recipient of that key material. At time of publication, there are no publicly available patches.
CVE-2026-75524
OpenReception's appointment booking software provides an end-to-end encrypted appointment booking platform. Prior to version 2.2.2, an attacker overbooks an agent, placing multiple appointments into a single time slot that the system is designed to keep exclusive. The number of overlapping appointments equals the number of concurrent requests, and one booking token is enough because the token is consumed after the insert. This results in the integrity of the booking-calendar breaking and availability being denied to other clients. This issue has been patched in version 2.2.2.