CyberSecBulletin
CVE-2025-39783NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2025-39783 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 80ea6e6904fb2ba4ccb5d909579988466ec65358, d5aecddc3452371d9da82cdbb0c715812524b54b, dc4ffbd571716ff3b171418fb03abe80e720a7b1 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 80ea6e6904fb2ba4ccb5d909579988466ec65358 or d5aecddc3452371d9da82cdbb0c715812524b54b or dc4ffbd571716ff3b171418fb03abe80e720a7b1 or 409af8b9f7b4f23cd0464e71c6cd6fe13c076ae2, whichever matches your release line, or a later version.
  2. Update SIMATIC CN 4100 to V5.0 or a later version.
  3. Update Linux Kernel to 5.4.297 or 5.10.241 or 5.15.190 or 6.1.149, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, 80ea6e6904fb2ba4ccb5d909579988466ec65358; ef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, d5aecddc3452371d9da82cdbb0c715812524b54b; ef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, dc4ffbd571716ff3b171418fb03abe80e720a7b1; ef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, 409af8b9f7b4f23cd0464e71c6cd6fe13c076ae2; ef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, 0758862386f114d9ab1e23181461bd1e2e9ec4c6; ef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, 6cf65505523224cab1449d726d2ce8180c2941ee; ef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, a302bd89db35d8b7e279de4d2b41c16c7f191069; ef1433f717a2c63747a519d86965d73ff9bd08b3 up to, but not including, d79123d79a8154b4318529b7b2ff7e15806f480b; and 1 more ranges80ea6e6904fb2ba4ccb5d909579988466ec65358, d5aecddc3452371d9da82cdbb0c715812524b54b, dc4ffbd571716ff3b171418fb03abe80e720a7b1, 409af8b9f7b4f23cd0464e71c6cd6fe13c076ae2, 0758862386f114d9ab1e23181461bd1e2e9ec4c6, 6cf65505523224cab1449d726d2ce8180c2941ee
SiemensSIMATIC CN 4100before V5.0V5.0
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
LinuxLinux Kernel4.18 up to, but not including, 5.4.297; 5.5 up to, but not including, 5.10.241; 5.11 up to, but not including, 5.15.190; 5.16 up to, but not including, 6.1.149; 6.2 up to, but not including, 6.6.103; 6.7 up to, but not including, 6.12.44; 6.13 up to, but not including, 6.16.45.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.44
DebianDebian Linux11.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: PCI: endpoint: Fix configfs group list head handling Doing a list_del() on the epf_group field of struct pci_epf_driver in pci_epf_remove_cfs() is not correct as this field is a list head, not a list entry. This list_del() call triggers a KASAN warning when an endpoint function driver which has a configfs attribute group is torn down: ================================================================== BUG: KASAN: slab-use-after-free in pci_epf_remove_cfs+0x17c/0x198 Write of size 8 at addr ffff00010f4a0d80 by task rmmod/319 CPU: 3 UID: 0 PID: 319 Comm: rmmod Not tainted 6.16.0-rc2 #1 NONE Hardware name: Radxa ROCK 5B (DT) Call trace: show_stack+0x2c/0x84 (C) dump_stack_lvl+0x70/0x98 print_report+0x17c/0x538 kasan_report+0xb8/0x190 __asan_report_store8_noabort+0x20/0x2c pci_epf_remove_cfs+0x17c/0x198 pci_epf_unregister_driver+0x18/0x30 nvmet_pci_epf_cleanup_module+0x24/0x30 [nvmet_pci_epf] __arm64_sys_delete_module+0x264/0x424 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xac/0x230 do_el0_svc+0x40/0x58 el0_svc+0x48/0xdc el0t_64_sync_handler+0x10c/0x138 el0t_64_sync+0x198/0x19c ... Remove this incorrect list_del() call from pci_epf_remove_cfs().

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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