CyberSecBulletin
CVE-2026-68376NVD status: Received

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-68376 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 317731d01b03c529809df36d3a7d149677a8729d, 0528485f27016a42804abe01aa61b39d85fa803e, ee5e65964f456adfe14d526fba0bd055de98ecf3 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 0.6% 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 317731d01b03c529809df36d3a7d149677a8729d or 0528485f27016a42804abe01aa61b39d85fa803e or ee5e65964f456adfe14d526fba0bd055de98ecf3 or 0b4414e43e0861d67276031cc21401d7e87de3da, whichever matches your release line, or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 317731d01b03c529809df36d3a7d149677a8729d; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 0528485f27016a42804abe01aa61b39d85fa803e; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, ee5e65964f456adfe14d526fba0bd055de98ecf3; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 0b4414e43e0861d67276031cc21401d7e87de3da; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, d0a59ba58578e2b330fff80a44fe519f3ba7d8c7; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, a8d20ba0ab518c9ccbcde258f25fc1ee6e51d5db; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, 3aa40c3bccac2312ea7cf97f329190637f972b5d; 1f485649f52929d9937b346a920a522a7363e202 up to, but not including, e0b5252a59383b77d1b8dbeda00b7184dd95f4d3; and 1 more ranges317731d01b03c529809df36d3a7d149677a8729d, 0528485f27016a42804abe01aa61b39d85fa803e, ee5e65964f456adfe14d526fba0bd055de98ecf3, 0b4414e43e0861d67276031cc21401d7e87de3da, d0a59ba58578e2b330fff80a44fe519f3ba7d8c7, a8d20ba0ab518c9ccbcde258f25fc1ee6e51d5db

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
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
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:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix auth_hmacs array size in struct sctp_cookie The auth_hmacs array in struct sctp_cookie is supposed to store a complete SCTP_AUTH_HMAC_ALGO parameter, which consists of a struct sctp_paramhdr followed by N HMAC identifiers. However, the array size was calculated using an extra 2 bytes instead of sizeof(struct sctp_paramhdr), which is 4 bytes. When four HMAC identifiers are configured, the HMAC-ALGO parameter stored in the endpoint is larger than the auth_hmacs buffer in the cookie. As a result, sctp_association_init() copies beyond the end of auth_hmacs when initializing the association, corrupting the adjacent auth_chunks field. This can lead to an invalid HMAC identifier being accepted and later cause an out-of-bounds read in sctp_auth_get_hmac(). Fix the array size calculation by including the full SCTP parameter header size.

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: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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