CVE-2026-46086
Essential information
- Published
- 27/05/2026 16:17
- Modified
- —
- Author
- The MITRE Corporation
- Creator
- The MITRE Corporation
- CVSS
- 5.5 MEDIUM (v3.1)
- CISA KEV
- No
- CWE
- CWE-476
- EPSS (First)
- P7.3% EPSS percentile: rank of this vulnerability versus all others. Higher percentile = more likely to be exploited. Learn more (score 0.00177)
- CVSS vector
-
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CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H—
CVSS metrics
- Access vector
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- Access complexity
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- Authentication
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- Confidentiality impact
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- Integrity impact
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- Availability impact
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- Exploitability
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- Remediation level
- —
- Report confidence
- —
- Temporal score
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- Attack vector
- LOCAL
- Attack complexity
- LOW
- Privileges required
- LOW
- User interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality impact
- NONE
- Integrity impact
- NONE
- Availability impact
- HIGH
- Exploit code maturity
- —
- Remediation level
- —
- Report confidence
- —
- Temporal score
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- Attack vector
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- Attack complexity
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- Attack requirements
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- Privileges required
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- User interaction
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- Confidentiality (V)
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- Confidentiality (S)
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- Integrity (V)
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- Integrity (S)
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- Availability (V)
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- Availability (S)
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- Exploit maturity
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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.
NVD status
- NVD
- View on NVD