0.0
NA
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
Call skb_cow_data() before in-place crypto operations to prevent data corruption and use-after-free.
  • 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.
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
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.