CyberSecBulletin
CVE-2026-43205NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-43205 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 a26dda3bae469c8e4e1b1993ad33dafa32d0fc28, a3034a8d56174dd6464c46823438f25797910a8d, b690635d4719214892855b79ce018d4b1672ac96 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 0.14% 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 a26dda3bae469c8e4e1b1993ad33dafa32d0fc28 or a3034a8d56174dd6464c46823438f25797910a8d or b690635d4719214892855b79ce018d4b1672ac96 or 8b841fd529db9faf8bc678d429d4bf4e98b10900, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.15.202 or 6.1.165 or 6.6.128 or 6.12.75, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux539dda3c5d190c5088b5e57944b1b482fcb464de up to, but not including, a26dda3bae469c8e4e1b1993ad33dafa32d0fc28; 539dda3c5d190c5088b5e57944b1b482fcb464de up to, but not including, a3034a8d56174dd6464c46823438f25797910a8d; 539dda3c5d190c5088b5e57944b1b482fcb464de up to, but not including, b690635d4719214892855b79ce018d4b1672ac96; 539dda3c5d190c5088b5e57944b1b482fcb464de up to, but not including, 8b841fd529db9faf8bc678d429d4bf4e98b10900; 539dda3c5d190c5088b5e57944b1b482fcb464de up to, but not including, 89764cf44544e943230f5e03b8c40a90da26537c; 539dda3c5d190c5088b5e57944b1b482fcb464de up to, but not including, c18493f750208eb4ff1198fc5a02786b8b2d70a6; 539dda3c5d190c5088b5e57944b1b482fcb464de up to, but not including, 8a5752c6dcc085a3bfc78589925182e4e98468c5; 5.13a26dda3bae469c8e4e1b1993ad33dafa32d0fc28, a3034a8d56174dd6464c46823438f25797910a8d, b690635d4719214892855b79ce018d4b1672ac96, 8b841fd529db9faf8bc678d429d4bf4e98b10900, 89764cf44544e943230f5e03b8c40a90da26537c, c18493f750208eb4ff1198fc5a02786b8b2d70a6
LinuxLinux Kernel5.13 up to, but not including, 5.15.202; 5.16 up to, but not including, 6.1.165; 6.2 up to, but not including, 6.6.128; 6.7 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.16; 6.19 up to, but not including, 6.19.6; 7.05.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16, 6.19.6

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: dpaa2-switch: validate num_ifs to prevent out-of-bounds write The driver obtains sw_attr.num_ifs from firmware via dpsw_get_attributes() but never validates it against DPSW_MAX_IF (64). This value controls iteration in dpaa2_switch_fdb_get_flood_cfg(), which writes port indices into the fixed-size cfg->if_id[DPSW_MAX_IF] array. When firmware reports num_ifs >= 64, the loop can write past the array bounds. Add a bound check for num_ifs in dpaa2_switch_init(). dpaa2_switch_fdb_get_flood_cfg() appends the control interface (port num_ifs) after all matched ports. When num_ifs == DPSW_MAX_IF and all ports match the flood filter, the loop fills all 64 slots and the control interface write overflows by one entry. The check uses >= because num_ifs == DPSW_MAX_IF is also functionally broken. build_if_id_bitmap() silently drops any ID >= 64: if (id[i] < DPSW_MAX_IF) bmap[id[i] / 64] |= ...

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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