CVE-2026-64026
rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg
Description
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg This improves the fix for CVE-2026-43500. Fix the pagecache corruption from in-place decryption of a DATA packet transmitted locally by splice() by getting rid of the packet sharing in the I/O thread and unconditionally extracting the packet content into a bounce buffer in which the buffer is decrypted. recvmsg() (or the kernel equivalent) then copies the data from the bounce buffer to the destination buffer. The sk_buff then remains unmodified. This has an additional advantage in that the packet is then arranged in the buffer with the correct alignment required for the crypto algorithms to process directly. The performance of the crypto does seem to be a little faster and, surprisingly, the unencrypted performance doesn't seem to change much - possibly due to removing complexity from the I/O thread. Yet another advantage is that the I/O thread doesn't have to copy packets which would slow down packet distribution, ACK generation, etc.. The buffer belongs to the call and is allocated initially at 2K, sufficiently large to hold a whole jumbo subpacket, but the buffer will be increased in size if needed. However, to take this work, MSG_PEEK may cause a later packet to be decrypted into the buffer, in which case the earlier one will need re-decrypting for a subsequent recvmsg(). Note that rx_pkt_offset may legitimately see 0 as a valid offset now, so switch to using USHRT_MAX to indicate an invalid offset. Note also that I would generally prefer to replace the buffers of the current sk_buff with a new kmalloc'd buffer of the right size, ditching the old data and frags as this makes the handling of MSG_PEEK easier and removes the re-decryption issue, but this looks like quite a complicated thing to achieve. skb_morph() looks half way to what I want, but I don't want to have to allocate a new sk_buff.
INFO
Published Date :
July 19, 2026, 4:17 p.m.
Last Modified :
July 30, 2026, 2:59 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Apply the provided kernel patch.
- Ensure data is copied to a bounce buffer.
- Decrypt data within the bounce buffer.
- Update rx_pkt_offset handling.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64026.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64026 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64026
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-64026 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64026 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 19, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'd0d5c0cd1e711c98703f3544c1e6fc1372898de5', 'lessThan': 'a05bf6d9e621fa71e89ccebe3047ba45218d7b38', 'versionType': 'git'}, {'status': 'affected', 'version': 'd0d5c0cd1e711c98703f3544c1e6fc1372898de5', 'lessThan': 'b94a6ccbaf1104dd980150a65fdeb2f69d17d2f5', 'versionType': 'git'}, {'status': 'affected', 'version': 'd0d5c0cd1e711c98703f3544c1e6fc1372898de5', 'lessThan': '46cb765e2e5ad52303ea157e10d370bb6b7acbbf', 'versionType': 'git'}, {'status': 'affected', 'version': 'd0d5c0cd1e711c98703f3544c1e6fc1372898de5', 'lessThan': 'c580087743712112778a06d65a4074053072d7bf', 'versionType': 'git'}, {'status': 'affected', 'version': 'd0d5c0cd1e711c98703f3544c1e6fc1372898de5', 'lessThan': 'd2bc90cf6c75cb96d2ce549be6c35efa3099d25b', 'versionType': 'git'}], 'programFiles': ['net/rxrpc/ar-internal.h', 'net/rxrpc/call_event.c', 'net/rxrpc/call_object.c', 'net/rxrpc/insecure.c', 'net/rxrpc/recvmsg.c', 'net/rxrpc/rxgk.c', 'net/rxrpc/rxgk_common.h', 'net/rxrpc/rxkad.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.3'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.3', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.93', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.35', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.11', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/rxrpc/ar-internal.h', 'net/rxrpc/call_event.c', 'net/rxrpc/call_object.c', 'net/rxrpc/insecure.c', 'net/rxrpc/recvmsg.c', 'net/rxrpc/rxgk.c', 'net/rxrpc/rxgk_common.h', 'net/rxrpc/rxkad.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg This improves the fix for CVE-2026-43500. Fix the pagecache corruption from in-place decryption of a DATA packet transmitted locally by splice() by getting rid of the packet sharing in the I/O thread and unconditionally extracting the packet content into a bounce buffer in which the buffer is decrypted. recvmsg() (or the kernel equivalent) then copies the data from the bounce buffer to the destination buffer. The sk_buff then remains unmodified. This has an additional advantage in that the packet is then arranged in the buffer with the correct alignment required for the crypto algorithms to process directly. The performance of the crypto does seem to be a little faster and, surprisingly, the unencrypted performance doesn't seem to change much - possibly due to removing complexity from the I/O thread. Yet another advantage is that the I/O thread doesn't have to copy packets which would slow down packet distribution, ACK generation, etc.. The buffer belongs to the call and is allocated initially at 2K, sufficiently large to hold a whole jumbo subpacket, but the buffer will be increased in size if needed. However, to take this work, MSG_PEEK may cause a later packet to be decrypted into the buffer, in which case the earlier one will need re-decrypting for a subsequent recvmsg(). Note that rx_pkt_offset may legitimately see 0 as a valid offset now, so switch to using USHRT_MAX to indicate an invalid offset. Note also that I would generally prefer to replace the buffers of the current sk_buff with a new kmalloc'd buffer of the right size, ditching the old data and frags as this makes the handling of MSG_PEEK easier and removes the re-decryption issue, but this looks like quite a complicated thing to achieve. skb_morph() looks half way to what I want, but I don't want to have to allocate a new sk_buff. Added Reference https://git.kernel.org/stable/c/46cb765e2e5ad52303ea157e10d370bb6b7acbbf Added Reference https://git.kernel.org/stable/c/a05bf6d9e621fa71e89ccebe3047ba45218d7b38 Added Reference https://git.kernel.org/stable/c/b94a6ccbaf1104dd980150a65fdeb2f69d17d2f5 Added Reference https://git.kernel.org/stable/c/c580087743712112778a06d65a4074053072d7bf Added Reference https://git.kernel.org/stable/c/d2bc90cf6c75cb96d2ce549be6c35efa3099d25b