5.5
MEDIUM
CVSS 3.1
CVE-2026-46086
net: bridge: use a stable FDB dst snapshot in RCU readers
Overview
Description
In the Linux kernel, the following vulnerability has been resolved: net: bridge: use a stable FDB dst snapshot in RCU readers Local FDB entries can be rewritten in place by `fdb_delete_local()`, which updates `f->dst` to another port or to `NULL` while keeping the entry alive. Several bridge RCU readers inspect `f->dst`, including `br_fdb_fillbuf()` through the `brforward_read()` sysfs path. These readers currently load `f->dst` multiple times and can therefore observe inconsistent values across the check and later dereference. In `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change `f->dst` after the NULL check and before the `port_no` dereference, leading to a NULL-ptr-deref. Fix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each affected RCU reader and using that snapshot for the rest of the access sequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()` with `WRITE_ONCE()` so the readers and writer use matching access patterns.
Details
INFO
Published Date :
May 27, 2026, 2:17 p.m.
Last Modified :
June 24, 2026, 5:08 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
Apply kernel updates to fix a NULL-ptr-deref vulnerability.
- Update the Linux kernel.
- Ensure RCU readers use stable snapshots.
- Publish FDB updates with WRITE_ONCE.
References
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-2026-46086.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-46086 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-2026-46086
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-2026-46086 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-46086 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.
-
Initial Analysis by [email protected]
Jun. 24, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-476 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:3.14:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:3.14:rc7:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:3.14:rc8:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:3.14:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:3.14:-:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:3.14:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:3.14:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.86 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.140 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.27 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.4 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 3.14.1 up to (excluding) 5.10.259 Added Reference Type kernel.org: https://git.kernel.org/stable/c/0b9e4bbfb7c949151e3acd44ed4aa33614d2e110 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/5424e678f9b304e148cf5dcc047cffc7a56a3bb5 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/81af4137a30c4c2dc694dea8cacb180bd66000ef Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/9a2d9d4e657b23dc21f24cf139e3aeff0b61341f Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/a6ae4511c07b91f597e461406c6330f0d4ff810e Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/c502fa9f094cb03d1d1685c71e2105ab359bc2b8 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/df4601653201de21b487c3e7fffd464790cab808 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 19, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a Added Reference https://git.kernel.org/stable/c/a6ae4511c07b91f597e461406c6330f0d4ff810e Added Reference https://git.kernel.org/stable/c/c502fa9f094cb03d1d1685c71e2105ab359bc2b8 Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '0b9e4bbfb7c949151e3acd44ed4aa33614d2e110', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '81af4137a30c4c2dc694dea8cacb180bd66000ef', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '5424e678f9b304e148cf5dcc047cffc7a56a3bb5', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '9a2d9d4e657b23dc21f24cf139e3aeff0b61341f', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': 'df4601653201de21b487c3e7fffd464790cab808', 'versionType': 'git'}], 'programFiles': ['net/bridge/br_arp_nd_proxy.c', 'net/bridge/br_fdb.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.140', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.86', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.27', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.4', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bridge/br_arp_nd_proxy.c', 'net/bridge/br_fdb.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': 'c502fa9f094cb03d1d1685c71e2105ab359bc2b8', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': 'a6ae4511c07b91f597e461406c6330f0d4ff810e', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '0b9e4bbfb7c949151e3acd44ed4aa33614d2e110', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '81af4137a30c4c2dc694dea8cacb180bd66000ef', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '5424e678f9b304e148cf5dcc047cffc7a56a3bb5', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '9a2d9d4e657b23dc21f24cf139e3aeff0b61341f', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': 'df4601653201de21b487c3e7fffd464790cab808', 'versionType': 'git'}], 'programFiles': ['net/bridge/br_arp_nd_proxy.c', 'net/bridge/br_fdb.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.259', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.210', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.140', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.86', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.27', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.4', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bridge/br_arp_nd_proxy.c', 'net/bridge/br_fdb.c'], 'defaultStatus': 'affected'}] -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 17, 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': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '0b9e4bbfb7c949151e3acd44ed4aa33614d2e110', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '81af4137a30c4c2dc694dea8cacb180bd66000ef', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '5424e678f9b304e148cf5dcc047cffc7a56a3bb5', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': '9a2d9d4e657b23dc21f24cf139e3aeff0b61341f', 'versionType': 'git'}, {'status': 'affected', 'version': '960b589f86c74ce582922fcb996103271081f4de', 'lessThan': 'df4601653201de21b487c3e7fffd464790cab808', 'versionType': 'git'}], 'programFiles': ['net/bridge/br_arp_nd_proxy.c', 'net/bridge/br_fdb.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '3.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.140', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.86', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.27', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.4', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bridge/br_arp_nd_proxy.c', 'net/bridge/br_fdb.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 27, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: net: bridge: use a stable FDB dst snapshot in RCU readers Local FDB entries can be rewritten in place by `fdb_delete_local()`, which updates `f->dst` to another port or to `NULL` while keeping the entry alive. Several bridge RCU readers inspect `f->dst`, including `br_fdb_fillbuf()` through the `brforward_read()` sysfs path. These readers currently load `f->dst` multiple times and can therefore observe inconsistent values across the check and later dereference. In `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change `f->dst` after the NULL check and before the `port_no` dereference, leading to a NULL-ptr-deref. Fix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each affected RCU reader and using that snapshot for the rest of the access sequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()` with `WRITE_ONCE()` so the readers and writer use matching access patterns. Added Reference https://git.kernel.org/stable/c/0b9e4bbfb7c949151e3acd44ed4aa33614d2e110 Added Reference https://git.kernel.org/stable/c/5424e678f9b304e148cf5dcc047cffc7a56a3bb5 Added Reference https://git.kernel.org/stable/c/81af4137a30c4c2dc694dea8cacb180bd66000ef Added Reference https://git.kernel.org/stable/c/9a2d9d4e657b23dc21f24cf139e3aeff0b61341f Added Reference https://git.kernel.org/stable/c/df4601653201de21b487c3e7fffd464790cab808
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.