Linux: Use After Free
CVE-2026-46227 is a high-severity use after free 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 f3a3f0b406b4b7eb3cea35a23fa2bf170848b104, 0dbc8cde64280fc37cdd678cced34eaf96cfb197, 0c7b55974f97b78d1109025eadf084e74cbf330f 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 0.1% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to f3a3f0b406b4b7eb3cea35a23fa2bf170848b104 or 0dbc8cde64280fc37cdd678cced34eaf96cfb197 or 0c7b55974f97b78d1109025eadf084e74cbf330f or 1bfb06ecb00f7fdf35dba8e8f2877346cbe5e078, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.258 or 5.15.209 or 6.1.175 or 6.6.140, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, f3a3f0b406b4b7eb3cea35a23fa2bf170848b104; 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, 0dbc8cde64280fc37cdd678cced34eaf96cfb197; 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, 0c7b55974f97b78d1109025eadf084e74cbf330f; 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, 1bfb06ecb00f7fdf35dba8e8f2877346cbe5e078; 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, 6187a172d6ed57d6b2c327836e4407c6456e639d; 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, c9dadb31f36045a8cb65df4bd75e7237ef21a4b5; 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, bf0f40d8107e2ce827521968dc6926f3e13728ae; 4910280503f3af2857d5aa77e35b22d93a8960a8 up to, but not including, abb5f36771cc4c05899b34000829a787572a8817; and 1 more ranges | f3a3f0b406b4b7eb3cea35a23fa2bf170848b104, 0dbc8cde64280fc37cdd678cced34eaf96cfb197, 0c7b55974f97b78d1109025eadf084e74cbf330f, 1bfb06ecb00f7fdf35dba8e8f2877346cbe5e078, 6187a172d6ed57d6b2c327836e4407c6456e639d, c9dadb31f36045a8cb65df4bd75e7237ef21a4b5 |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 4.17 up to, but not including, 5.10.258; 5.11 up to, but not including, 5.15.209; 5.16 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.140; 6.7 up to, but not including, 6.12.90; 6.13 up to, but not including, 6.18.32; 6.19 up to, but not including, 7.0.9; 7.1 | 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.90, 6.18.32 |
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 CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.0 | High | CNA |
Official description
In the Linux kernel, the following vulnerability has been resolved: sctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL The SCTP_SENDALL path in sctp_sendmsg() iterates ep->asocs with list_for_each_entry_safe(), which caches the next entry in @tmp before the loop body runs. The body calls sctp_sendmsg_to_asoc(), which may drop the socket lock inside sctp_wait_for_sndbuf(). While the lock is dropped, another thread can SCTP_SOCKOPT_PEELOFF the association cached in @tmp, migrating it to a new endpoint via sctp_sock_migrate() (list_del_init() + list_add_tail() to newep->asocs), and optionally close the new socket which frees the association via kfree_rcu(). The cached @tmp can also be freed by a network ABORT for that association, processed in softirq while the lock is dropped. sctp_wait_for_sndbuf() revalidates @asoc (the current entry) on re-lock via the "sk != asoc->base.sk" and "asoc->base.dead" checks, but nothing revalidates @tmp. After a successful return, the iterator advances to the stale @tmp, yielding either a use-after-free (if the peeled socket was closed) or a list-walk onto the new endpoint's list head (type confusion of &newep->asocs as a struct sctp_association *). Both are reachable from CapEff=0; the type-confusion path gives controlled indirect call via the outqueue.sched->init_sid pointer. Fix by re-deriving @tmp from @asoc after sctp_sendmsg_to_asoc() returns. @asoc is known to still be on ep->asocs at that point: the only callers that list_del an association from ep->asocs are sctp_association_free() (which sets asoc->base.dead) and sctp_assoc_migrate() (which changes asoc->base.sk), and sctp_wait_for_sndbuf() checks both under the lock before any successful return; a tripped check propagates as err < 0 and the loop bails before the re-derive. The SCTP_ABORT path in sctp_sendmsg_check_sflags() returns 0 and the loop hits 'continue' before sctp_sendmsg_to_asoc() is ever called, so the @tmp cached by list_for_each_entry_safe() still covers the lock-held free that ba59fb027307 ("sctp: walk the list of asoc safely") was added for.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/0c7b55974f97b78d1109025eadf084e74cbf330f
- git.kernel.org/stable/c/0dbc8cde64280fc37cdd678cced34eaf96cfb197
- git.kernel.org/stable/c/1bfb06ecb00f7fdf35dba8e8f2877346cbe5e078
- git.kernel.org/stable/c/6187a172d6ed57d6b2c327836e4407c6456e639d
- git.kernel.org/stable/c/abb5f36771cc4c05899b34000829a787572a8817
- git.kernel.org/stable/c/bf0f40d8107e2ce827521968dc6926f3e13728ae
- git.kernel.org/stable/c/c9dadb31f36045a8cb65df4bd75e7237ef21a4b5
- git.kernel.org/stable/c/f3a3f0b406b4b7eb3cea35a23fa2bf170848b104
Other references
- access.redhat.com/errata/RHSA-2026:26462
- access.redhat.com/errata/RHSA-2026:26515
- access.redhat.com/errata/RHSA-2026:26535
- access.redhat.com/errata/RHSA-2026:26563
- access.redhat.com/errata/RHSA-2026:27731
- access.redhat.com/errata/RHSA-2026:27735
- access.redhat.com/errata/RHSA-2026:33899
- access.redhat.com/errata/RHSA-2026:34094
- access.redhat.com/errata/RHSA-2026:36018
- access.redhat.com/errata/RHSA-2026:36348
- access.redhat.com/errata/RHSA-2026:36349
- access.redhat.com/errata/RHSA-2026:36956
- access.redhat.com/errata/RHSA-2026:59142
- access.redhat.com/errata/RHSA-2026:59143
- access.redhat.com/errata/RHSA-2026:59145
Recent Use After Free vulnerabilities
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