{"id":"CVE-2025-38525","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix irq-disabled in local_bh_enable()\n\nThe rxrpc_assess_MTU_size() function calls down into the IP layer to find\nout the MTU size for a route","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix irq-disabled in local_bh_enable()\n\nThe rxrpc_assess_MTU_size() function calls down into the IP layer to find\nout the MTU size for a route.  When accepting an…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 6.14, < 6.15.8","linux_kernel = 6.16"],"patched":["linux_kernel 6.15.8"],"published":"2025-08-16","updated":"2026-08-03","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-38525","references":[{"url":"https://git.kernel.org/stable/c/2029f21f10dedb88c0f86abffcf8d6c21dcf6040","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e4d2878369d590bf8455e3678a644e503172eafa","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00364,"epssPercentile":0.30303,"ingestedAt":"2026-08-03T10:24:19.623Z","slug":"CVE-2025-38525","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix irq-disabled in local_bh_enable()\n\nThe rxrpc_assess_MTU_size() function calls down into the IP layer to find\nout the MTU size for a route.  When accepting an incoming call, this is\ncalled from rxrpc_new_incoming_call() which holds interrupts disabled\nacross the code that calls down to it.  Unfortunately, the IP layer uses\nlocal_bh_enable() which, config dependent, throws a warning if IRQs are\nenabled:\n\nWARNING: CPU: 1 PID: 5544 at kernel/softirq.c:387 __local_bh_enable_ip+0x43/0xd0\n...\nRIP: 0010:__local_bh_enable_ip+0x43/0xd0\n...\nCall Trace:\n <TASK>\n rt_cache_route+0x7e/0xa0\n rt_set_nexthop.isra.0+0x3b3/0x3f0\n __mkroute_output+0x43a/0x460\n ip_route_output_key_hash+0xf7/0x140\n ip_route_output_flow+0x1b/0x90\n rxrpc_assess_MTU_size.isra.0+0x2a0/0x590\n rxrpc_new_incoming_peer+0x46/0x120\n rxrpc_alloc_incoming_call+0x1b1/0x400\n rxrpc_new_incoming_call+0x1da/0x5e0\n rxrpc_input_packet+0x827/0x900\n rxrpc_io_thread+0x403/0xb60\n kthread+0x2f7/0x310\n ret_from_fork+0x2a/0x230\n ret_from_fork_asm+0x1a/0x30\n...\nhardirqs last  enabled at (23): _raw_spin_unlock_irq+0x24/0x50\nhardirqs last disabled at (24): _raw_read_lock_irq+0x17/0x70\nsoftirqs last  enabled at (0): copy_process+0xc61/0x2730\nsoftirqs last disabled at (25): rt_add_uncached_list+0x3c/0x90\n\nFix this by moving the call to rxrpc_assess_MTU_size() out of\nrxrpc_init_peer() and further up the stack where it can be done without\ninterrupts disabled.\n\nIt shouldn't be a problem for rxrpc_new_incoming_call() to do it after the\nlocks are dropped as pmtud is going to be performed by the I/O thread - and\nwe're in the I/O thread at this point.\n\n## Affected\n\n- `linux_kernel >= 6.14, < 6.15.8`\n- `linux_kernel = 6.16`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.15.8`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}