CVE-2026-13270
Quest NetVault Backup nvpmgr Integer Underflow Denial-of-Service Vulnerability. This vulnerability allows remote attackers to create a denia
CVSS
7.5
High
EPSS
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KEV
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Exploit Today
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0-100
Published: Nov 12, 2026 · Last modified: Nov 12, 2026 · CWE-191
Not enough EPSS history yet.
Quest NetVault Backup nvpmgr Integer Underflow Denial-of-Service Vulnerability. This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Quest NetVault Backup. Authentication is not required to exploit this vulnerability. The specific flaw exists within the nvpmgr service, which listens on UDP port 20031 by default. The issue results from the lack of proper validation of user-supplied data, which can result in an integer underflow before allocating a buffer. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-28744.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-1269575.3 MED—
———An integer underflow in Zephyr's IPv4 option handling allows a remote, unauthenticated attacker to read stack memory. When replying to an ICMP Echo Request that carries an IPv4 Record Route or Timestamp option, icmpv4_update_record_route() and icmpv4_update_time_stamp() in subsys/net/ip/icmpv4.c compute the length of the already recorded data as ptr - ptr_offset in uint8_t arithmetic. The attacker-controlled Pointer field is checked against the option length but not against the RFC 791 minimum (4 for Record Route, 5 for Timestamp), so a smaller value wraps the length to up to 252 bytes. net_pkt_write() then reads past the 40-byte opt_data stack buffer and up to 213 bytes of stack memory, which can include stack and heap pointers, are returned in the ICMP Echo Reply. A single packet triggers the leak and the device does not crash, so it can be repeated. Devices built with CONFIG_NET_IPV4_HDR_OPTIONS, which CONFIG_NET_IPV4_IGMP selects, are affected.4hCVE-2026-776858.3 HIG29.0%
——9The RFCOMM multiplexer control-channel handler in subsys/bluetooth/host/classic/rfcomm.c computed the echo length for a BT_RFCOMM_TEST command as buf->len - 1 and passed it to rfcomm_send_test(), whose length parameter is a uint8_t. A malformed but FCS-valid UIH frame on DLCI 0 can leave buf->len == 0 after rfcomm_handle_msg() pulls the two-byte MCC header, so buf->len - 1 underflows and narrows to 255.
rfcomm_send_test() then copies 255 bytes out of a receive buffer that holds no remaining valid data, and appends them to an outgoing L2CAP PDU allocated with only CONFIG_BT_L2CAP_TX_MTU (253 by default for CONFIG_BT_CLASSIC) bytes of tailroom. The source read runs past the end of the ACL receive buffer into adjacent buffers of the same net_buf pool, and the destination copy overruns the transmit buffer by about eight bytes; net_buf_add_mem() performs no runtime bounds check in ordinary builds, where the underlying __ASSERT_NO_MSG() is compiled out.
The trigger is a single five-byte RFCOMM frame on the multiplexer control channel, which is processed as soon as the L2CAP channel for PSM 3 is established — before any DLC exists and independent of RFCOMM session state. bt_rfcomm_init() registers that L2CAP server with .sec_level = BT_SECURITY_L1, which l2cap_br_conn_security() accepts without any link key from a peer that does not claim host Secure Simple Pairing support, so an unpaired BR/EDR device in radio range of a connectable target with CONFIG_BT_RFCOMM enabled (SPP, HFP, HSP, GOEP and similar profiles all enable it) can reach the defect.
The resulting 255-byte TEST response is transmitted back to the attacker, disclosing roughly 255 bytes of adjacent stack/pool memory — including the contents of neighbouring receive buffers, which an attacker can prime with earlier packets — and the accompanying out-of-bounds write corrupts memory following the transmit buffer, which can crash the Bluetooth host. The request is trivially repeatable, so both the disclosure and the corruption can be driven at will.
Two fixes are needed, and the first on its own does not close the out-of-bounds write. Fix 1 (0040ef781e1d, #115768) strips the FCS byte in rfcomm_recv() and echoes buf->len, rejecting anything over UINT8_MAX, which removes the underflow and the over-read. But rfcomm_make_uih_msg() still allocates the response with bt_l2cap_create_pdu() and never compares the requested length with the buffer's tailroom, so a well-formed TEST command carrying a pattern of about 248 bytes or more still builds a response (3-byte frame header, 2-byte message header, pattern, FCS) larger than the 253 bytes available. A pattern that long can only be received when the RFCOMM L2CAP receive MTU (CONFIG_BT_RFCOMM_L2CAP_MTU, which defaults to CONFIG_BT_BUF_ACL_RX_SIZE) exceeds CONFIG_BT_L2CAP_TX_MTU. The plain BR/EDR defaults (200 against 253) cannot reach it, but from v4.3.0 enabling CONFIG_BT_GOEP raises CONFIG_BT_BUF_ACL_RX_SIZE to 264 (265 from v4.4.0), so GOEP builds with only fix 1 applied still overrun the transmit buffer by up to eight bytes. This includes v4.3.2, the last v4.3 release, which carries fix 1 but will not receive fix 2. Fix 2 (214530895dd3, #118293) checks the tailroom on every RFCOMM PDU allocation and closes this residual write.1dCVE-2026-960789.8 CRI63.1%
——19Heap-based buffer overflow in Microsoft Color Management allows an unauthorized attacker to execute code over a network.1dCVE-2026-960527.8 HIG24.2%
——7Integer underflow (wrap or wraparound) in Windows Kernel allows an authorized attacker to elevate privileges locally.1dCVE-2026-960108.8 HIG60.5%
——18Integer underflow (wrap or wraparound) in HID Parser Library allows an authorized attacker to elevate privileges over a network.1dCVE-2026-959968.8 HIG53.1%
——16Integer underflow (wrap or wraparound) in Windows Bluetooth Port Driver allows an authorized attacker to elevate privileges over a network.1d