CVE-2026-63831
mac802154: llsec: add skb_cow_data() before in-place crypto
Description
In the Linux kernel, the following vulnerability has been resolved: mac802154: llsec: add skb_cow_data() before in-place crypto llsec_do_encrypt_unauth(), llsec_do_encrypt_auth(), llsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() all perform in-place cryptographic transformations on skb data. They build a scatterlist with sg_init_one() pointing into the skb's linear data area and then pass the same scatterlist as both src and dst to the crypto API (e.g. crypto_skcipher_encrypt/decrypt, crypto_aead_encrypt/decrypt). On the RX path, __ieee802154_rx_handle_packet() clones the received skb before handing it to each subscriber via ieee802154_subif_frame(). The cloned skb shares the same underlying data buffer via reference counting. When llsec_do_decrypt() subsequently modifies this shared buffer in place, it corrupts data that other clones -- potentially belonging to other sockets or subsystems -- still reference. On the TX path, similar data sharing can occur when an skb's head has been cloned (skb_cloned() returns true). The fix is to call skb_cow_data() before performing any in-place crypto operation. skb_cow_data() ensures that the skb's data area is not shared: if the skb head is cloned or the data spans multiple fragments, it copies the data into a private buffer that can be safely modified in place. This is the same pattern used by: - ESP (net/ipv4/esp4.c, net/ipv6/esp6.c) - MACsec (drivers/net/macsec.c) - WireGuard (drivers/net/wireguard/receive.c) - TIPC (net/tipc/crypto.c) Without this guard, in-place crypto on shared skb data leads to: - Silent data corruption of other skb clones - Use-after-free when the crypto API scatterwalk writes through a page that has already been freed by another clone's kfree_skb() - Kernel crashes under concurrent 802.15.4 traffic with security enabled (KASAN/KMSAN reports slab-use-after-free) Found by 0sec (https://0sec.ai) using automated source analysis.
INFO
Published Date :
July 19, 2026, 12:16 p.m.
Last Modified :
July 19, 2026, 12:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-63831
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Ensure skb_cow_data() is called before in-place crypto.
- Avoid in-place crypto on shared skb data.
- Apply the provided kernel patch for llsec.
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-2026-63831.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-63831 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-2026-63831
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).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-63831 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-63831 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.
-
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': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': '3a2b378b3a9ca75d3518d879148d2ad25b5714a9', 'versionType': 'git'}, {'status': 'affected', 'version': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': '7a831bcd0486788283ef35e396d4282ee01bb0d5', 'versionType': 'git'}, {'status': 'affected', 'version': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': 'ff976ef7c39199ebff33c18034636595016db9f0', 'versionType': 'git'}, {'status': 'affected', 'version': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': 'e28e7fd34c449028325322a3f5127b92594b7396', 'versionType': 'git'}, {'status': 'affected', 'version': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': '993fd674fe85d114e6a8d3963033d4fbbc2170a8', 'versionType': 'git'}, {'status': 'affected', 'version': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': 'bd968bdd568beacfdf98ec537a87527e85f1d0cf', 'versionType': 'git'}, {'status': 'affected', 'version': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': '86d531337ea1ba02d9f2bc830d07c683d9bfaade', 'versionType': 'git'}, {'status': 'affected', 'version': '03556e4d0dbbbf4af9df76f4a3839c86f6afb015', 'lessThan': '84a04eb5b210643bd67aab81ff805d32f62aa865', 'versionType': 'git'}], 'programFiles': ['net/mac802154/llsec.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.16'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.16', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.260', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.211', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.177', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.144', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.95', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.38', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.3', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/mac802154/llsec.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: mac802154: llsec: add skb_cow_data() before in-place crypto llsec_do_encrypt_unauth(), llsec_do_encrypt_auth(), llsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() all perform in-place cryptographic transformations on skb data. They build a scatterlist with sg_init_one() pointing into the skb's linear data area and then pass the same scatterlist as both src and dst to the crypto API (e.g. crypto_skcipher_encrypt/decrypt, crypto_aead_encrypt/decrypt). On the RX path, __ieee802154_rx_handle_packet() clones the received skb before handing it to each subscriber via ieee802154_subif_frame(). The cloned skb shares the same underlying data buffer via reference counting. When llsec_do_decrypt() subsequently modifies this shared buffer in place, it corrupts data that other clones -- potentially belonging to other sockets or subsystems -- still reference. On the TX path, similar data sharing can occur when an skb's head has been cloned (skb_cloned() returns true). The fix is to call skb_cow_data() before performing any in-place crypto operation. skb_cow_data() ensures that the skb's data area is not shared: if the skb head is cloned or the data spans multiple fragments, it copies the data into a private buffer that can be safely modified in place. This is the same pattern used by: - ESP (net/ipv4/esp4.c, net/ipv6/esp6.c) - MACsec (drivers/net/macsec.c) - WireGuard (drivers/net/wireguard/receive.c) - TIPC (net/tipc/crypto.c) Without this guard, in-place crypto on shared skb data leads to: - Silent data corruption of other skb clones - Use-after-free when the crypto API scatterwalk writes through a page that has already been freed by another clone's kfree_skb() - Kernel crashes under concurrent 802.15.4 traffic with security enabled (KASAN/KMSAN reports slab-use-after-free) Found by 0sec (https://0sec.ai) using automated source analysis. Added Reference https://git.kernel.org/stable/c/3a2b378b3a9ca75d3518d879148d2ad25b5714a9 Added Reference https://git.kernel.org/stable/c/7a831bcd0486788283ef35e396d4282ee01bb0d5 Added Reference https://git.kernel.org/stable/c/84a04eb5b210643bd67aab81ff805d32f62aa865 Added Reference https://git.kernel.org/stable/c/86d531337ea1ba02d9f2bc830d07c683d9bfaade Added Reference https://git.kernel.org/stable/c/993fd674fe85d114e6a8d3963033d4fbbc2170a8 Added Reference https://git.kernel.org/stable/c/bd968bdd568beacfdf98ec537a87527e85f1d0cf Added Reference https://git.kernel.org/stable/c/e28e7fd34c449028325322a3f5127b92594b7396 Added Reference https://git.kernel.org/stable/c/ff976ef7c39199ebff33c18034636595016db9f0