Summary
In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Clear port select...
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Clear port select structure when fail to create
Clear the port select structure on error so no stale values left after
definers are destroyed. That's because the mlx5_lag_destroy_definers()
always try to destroy all lag definers in the tt_map, so in the flow
below lag definers get double-destroyed and cause kernel crash:
mlx5_lag_port_sel_create()
mlx5_lag_create_definers()
mlx5_lag_create_definer() <- Failed on tt 1
mlx5_lag_destroy_definers() <- definers[tt=0] gets destroyed
mlx5_lag_port_sel_create()
mlx5_lag_create_definers()
mlx5_lag_create_definer() <- Failed on tt 0
mlx5_lag_destroy_definers() <- definers[tt=0] gets double-destroyed
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
Mem abort info:
ESR = 0x0000000096000005
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x05: level 1 translation fault
Data abort info:
ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 64k pages, 48-bit VAs, pgdp=0000000112ce2e00
[0000000000000008] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000
Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
Modules linked in: iptable_raw bonding ip_gre ip6_gre gre ip6_tunnel tunnel6 geneve ip6_udp_tunnel udp_tunnel ipip tunnel4 ip_tunnel rdma_ucm(OE) rdma_cm(OE) iw_cm(OE) ib_ipoib(OE) ib_cm(OE) ib_umad(OE) mlx5_ib(OE) ib_uverbs(OE) mlx5_fwctl(OE) fwctl(OE) mlx5_core(OE) mlxdevm(OE) ib_core(OE) mlxfw(OE) memtrack(OE) mlx_compat(OE) openvswitch nsh nf_conncount psample xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user xfrm_algo xt_addrtype iptable_filter iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter bridge stp llc netconsole overlay efi_pstore sch_fq_codel zram ip_tables crct10dif_ce qemu_fw_cfg fuse ipv6 crc_ccitt [last unloaded: mlx_compat(OE)]
CPU: 3 UID: 0 PID: 217 Comm: kworker/u53:2 Tainted: G OE 6.11.0+ #2
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
Workqueue: mlx5_lag mlx5_do_bond_work [mlx5_core]
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : mlx5_del_flow_rules+0x24/0x2c0 [mlx5_core]
lr : mlx5_lag_destroy_definer+0x54/0x100 [mlx5_core]
sp : ffff800085fafb00
x29: ffff800085fafb00 x28: ffff0000da0c8000 x27: 0000000000000000
x26: ffff0000da0c8000 x25: ffff0000da0c8000 x24: ffff0000da0c8000
x23: ffff0000c31f81a0 x22: 0400000000000000 x21: ffff0000da0c8000
x20: 0000000000000000 x19: 0000000000000001 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffff8b0c9350
x14: 0000000000000000 x13: ffff800081390d18 x12: ffff800081dc3cc0
x11: 0000000000000001 x10: 0000000000000b10 x9 : ffff80007ab7304c
x8 : ffff0000d00711f0 x7 : 0000000000000004 x6 : 0000000000000190
x5 : ffff00027edb3010 x4 : 0000000000000000 x3 : 0000000000000000
x2 : ffff0000d39b8000 x1 : ffff0000d39b8000 x0 : 0400000000000000
Call trace:
mlx5_del_flow_rules+0x24/0x2c0 [mlx5_core]
mlx5_lag_destroy_definer+0x54/0x100 [mlx5_core]
mlx5_lag_destroy_definers+0xa0/0x108 [mlx5_core]
mlx5_lag_port_sel_create+0x2d4/0x6f8 [mlx5_core]
mlx5_activate_lag+0x60c/0x6f8 [mlx5_core]
mlx5_do_bond_work+0x284/0x5c8 [mlx5_core]
process_one_work+0x170/0x3e0
worker_thread+0x2d8/0x3e0
kthread+0x11c/0x128
ret_from_fork+0x10/0x20
Code: a9025bf5 aa0003f6 a90363f7 f90023f9 (f9400400)
---[ end trace 0000000000000000 ]---
Impact
The application dereferences a null pointer, causing a crash. Typical impact: denial of service via crash.
CVE-2025-21675 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-21675? CVE-2025-21675 is a medium-severity null pointer dereference vulnerability. No fixed version is listed yet. The application dereferences a null pointer, causing a crash.
- How severe is CVE-2025-21675? CVE-2025-21675 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-21675? No fixed version is listed for CVE-2025-21675 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-21675 exploitable, and should I be worried? Whether CVE-2025-21675 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-21675 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.