{"cve":"CVE-2026-23438","nvd":{"published":"2026-04-03T16:16:25.540","modified":"2026-10-15T02:18:56.570","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mvpp2: guard flow control update with global_tx_fc in buffer switching\n\nmvpp2_bm_switch_buffers() unconditionally calls\nmvpp2_bm_pool_update_priv_fc() when switching between per-cpu and\nshared buffer pool modes. This function programs CM3 flow control\nregisters via mvpp2_cm3_read()/mvpp2_cm3_write(), which dereference\npriv->cm3_base without any NULL check.\n\nWhen the CM3 SRAM resource is not present in the device tree (the\nthird reg entry added by commit 60523583b07c (\"dts: marvell: add CM3\nSRAM memory to cp11x ethernet device tree\")), priv->cm3_base remains\nNULL and priv->global_tx_fc is false. Any operation that triggers\nmvpp2_bm_switch_buffers(), for example an MTU change that crosses\nthe jumbo frame threshold, will crash:\n\n  Unable to handle kernel NULL pointer dereference at\n  virtual address 0000000000000000\n  Mem abort info:\n    ESR = 0x0000000096000006\n    EC = 0x25: DABT (current EL), IL = 32 bits\n  pc : readl+0x0/0x18\n  lr : mvpp2_cm3_read.isra.0+0x14/0x20\n  Call trace:\n   readl+0x0/0x18\n   mvpp2_bm_pool_update_fc+0x40/0x12c\n   mvpp2_bm_pool_update_priv_fc+0x94/0xd8\n   mvpp2_bm_switch_buffers.isra.0+0x80/0x1c0\n   mvpp2_change_mtu+0x140/0x380\n   __dev_set_mtu+0x1c/0x38\n   dev_set_mtu_ext+0x78/0x118\n   dev_set_mtu+0x48/0xa8\n   dev_ifsioc+0x21c/0x43c\n   dev_ioctl+0x2d8/0x42c\n   sock_ioctl+0x314/0x378\n\nEvery other flow control call site in the driver already guards\nhardware access with either priv->global_tx_fc or port->tx_fc.\nmvpp2_bm_switch_buffers() is the only place that omits this check.\n\nAdd the missing priv->global_tx_fc guard to both the disable and\nre-enable calls in mvpp2_bm_switch_buffers(), consistent with the\nrest of the driver.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-476"],"references":["https://git.kernel.org/stable/c/0cfcd31f98fc608dc9406bff3fee3a9dd364d014","https://git.kernel.org/stable/c/7bd20f4b3ef3044dc55acd5b8ef748a70d29d03f","https://git.kernel.org/stable/c/7df2b50cae1a76cbb90b294f3edb61e3e10bf2e9","https://git.kernel.org/stable/c/8a63baadf08453f66eb582fdb6dd234f72024723","https://git.kernel.org/stable/c/8baced53a35fc9710f80d6ca016a2c418dc3231f"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:28:59.047572785+00:00"},"epss":{"cve":"CVE-2026-23438","score":0.00129,"percentile":0.02497,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}