CyberSecBulletin
CVE-2026-68320NVD status: Received

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-68320 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.3 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 3d22a7da2e264f407c729f33a0a346ff76108bc6, 6837c1c19a259518974cbc5a52017646e3906564, 54bb4c03fa17cdcb157c26c33e60a78cf32960f5 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 0.13% 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 3d22a7da2e264f407c729f33a0a346ff76108bc6 or 6837c1c19a259518974cbc5a52017646e3906564 or 54bb4c03fa17cdcb157c26c33e60a78cf32960f5 or 5a365f1e423444c5da7eb689a8661633dad43e48, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 3d22a7da2e264f407c729f33a0a346ff76108bc6; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 6837c1c19a259518974cbc5a52017646e3906564; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 54bb4c03fa17cdcb157c26c33e60a78cf32960f5; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 5a365f1e423444c5da7eb689a8661633dad43e48; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 886e28e14ab655012779016d251fef53d103aa12; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 11092d79eb2b7c0068382f72fc2416d1786bb2e0; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, b6ea3dda09eb4d5caf7bbc00f857688cf9e98255; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, ff04b26794a16a8a879eb4fd2c02c2d6b03850e9; and 1 more ranges3d22a7da2e264f407c729f33a0a346ff76108bc6, 6837c1c19a259518974cbc5a52017646e3906564, 54bb4c03fa17cdcb157c26c33e60a78cf32960f5, 5a365f1e423444c5da7eb689a8661633dad43e48, 886e28e14ab655012779016d251fef53d103aa12, 11092d79eb2b7c0068382f72fc2416d1786bb2e0

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
LowSome restricted data 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:L/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix auth_chunk_list capacity check in sctp_auth_ep_add_chunkid sctp_auth_ep_add_chunkid() uses SCTP_NUM_CHUNK_TYPES (20) as the capacity limit for ep->auth_chunk_list, allowing it to hold up to 20 chunk entries (param_hdr.length up to 24). However, the copy destination asoc->c.auth_chunks in struct sctp_cookie is only SCTP_AUTH_MAX_CHUNKS (16) entries (20 bytes). When more than 16 chunks are added, sctp_association_init() memcpy overflows the destination by up to 4 bytes. Fix by using SCTP_AUTH_MAX_CHUNKS as the capacity limit, matching the destination capacity.

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. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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