CVE-2025-38525

Published Aug 16, 2025

Last updated 2 months ago

CVSS high 7.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix irq-disabled in local_bh_enable() The rxrpc_assess_MTU_size() function calls down into the IP layer to find out the MTU size for a route. When accepting an incoming call, this is called from rxrpc_new_incoming_call() which holds interrupts disabled across the code that calls down to it. Unfortunately, the IP layer uses local_bh_enable() which, config dependent, throws a warning if IRQs are enabled: WARNING: CPU: 1 PID: 5544 at kernel/softirq.c:387 __local_bh_enable_ip+0x43/0xd0 ... RIP: 0010:__local_bh_enable_ip+0x43/0xd0 ... Call Trace: <TASK> rt_cache_route+0x7e/0xa0 rt_set_nexthop.isra.0+0x3b3/0x3f0 __mkroute_output+0x43a/0x460 ip_route_output_key_hash+0xf7/0x140 ip_route_output_flow+0x1b/0x90 rxrpc_assess_MTU_size.isra.0+0x2a0/0x590 rxrpc_new_incoming_peer+0x46/0x120 rxrpc_alloc_incoming_call+0x1b1/0x400 rxrpc_new_incoming_call+0x1da/0x5e0 rxrpc_input_packet+0x827/0x900 rxrpc_io_thread+0x403/0xb60 kthread+0x2f7/0x310 ret_from_fork+0x2a/0x230 ret_from_fork_asm+0x1a/0x30 ... hardirqs last enabled at (23): _raw_spin_unlock_irq+0x24/0x50 hardirqs last disabled at (24): _raw_read_lock_irq+0x17/0x70 softirqs last enabled at (0): copy_process+0xc61/0x2730 softirqs last disabled at (25): rt_add_uncached_list+0x3c/0x90 Fix this by moving the call to rxrpc_assess_MTU_size() out of rxrpc_init_peer() and further up the stack where it can be done without interrupts disabled. It shouldn't be a problem for rxrpc_new_incoming_call() to do it after the locks are dropped as pmtud is going to be performed by the I/O thread - and we're in the I/O thread at this point.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

  1. CVE-2025-38525 Linux Kernel rxrpc Vulnerability https://t.co/AexhTJoFpg

    @VulmonFeeds

    16 Aug 2025

    73 Impressions

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Configurations

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References

Sources include official advisories and independent security research.