Answer in brief
CVE-2026-46086 records a Medium severity (CVSS 5.5) vulnerability in net: bridge: use a stable FDB dst snapshot in RCU readers. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-46086 records a Medium severity (CVSS 5.5) vulnerability in net: bridge: use a stable FDB dst snapshot in RCU readers. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=960b589f86c74ce582922fcb996103271081f4de <c502fa9f094cb03d1d1685c71e2105ab359bc2b8 || >=960b589f86c74ce582922fcb996103271081f4de <a6ae4511c07b91f597e461406c6330f0d4ff810e || >=960b589f86c74ce582922fcb996103271081f4de <1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a || >=960b589f86c74ce582922fcb996103271081f4de <0b9e4bbfb7c949151e3acd44ed4aa33614d2e110 || >=960b589f86c74ce582922fcb996103271081f4de <81af4137a30c4c2dc694dea8cacb180bd66000ef || >=960b589f86c74ce582922fcb996103271081f4de <5424e678f9b304e148cf5dcc047cffc7a56a3bb5 || >=960b589f86c74ce582922fcb996103271081f4de <9a2d9d4e657b23dc21f24cf139e3aeff0b61341f || >=960b589f86c74ce582922fcb996103271081f4de <df4601653201de21b487c3e7fffd464790cab808 | c502fa9f094cb03d1d1685c71e2105ab359bc2b8, a6ae4511c07b91f597e461406c6330f0d4ff810e, 1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a, 0b9e4bbfb7c949151e3acd44ed4aa33614d2e110, 81af4137a30c4c2dc694dea8cacb180bd66000ef, 5424e678f9b304e148cf5dcc047cffc7a56a3bb5, 9a2d9d4e657b23dc21f24cf139e3aeff0b61341f, df4601653201de21b487c3e7fffd464790cab808 |
| Linux/Linuxgeneric | 3.14 | Not reported |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 19, 2026
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.
Quoted source text, attributed separately from HOL analysis.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=960b589f86c74ce582922fcb996103271081f4de <c502fa9f094cb03d1d1685c71e2105ab359bc2b8 || >=960b589f86c74ce582922fcb996103271081f4de <a6ae4511c07b91f597e461406c6330f0d4ff810e || >=960b589f86c74ce582922fcb996103271081f4de <1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a || >=960b589f86c74ce582922fcb996103271081f4de <0b9e4bbfb7c949151e3acd44ed4aa33614d2e110 || >=960b589f86c74ce582922fcb996103271081f4de <81af4137a30c4c2dc694dea8cacb180bd66000ef || >=960b589f86c74ce582922fcb996103271081f4de <5424e678f9b304e148cf5dcc047cffc7a56a3bb5 || >=960b589f86c74ce582922fcb996103271081f4de <9a2d9d4e657b23dc21f24cf139e3aeff0b61341f || >=960b589f86c74ce582922fcb996103271081f4de <df4601653201de21b487c3e7fffd464790cab808 | c502fa9f094cb03d1d1685c71e2105ab359bc2b8, a6ae4511c07b91f597e461406c6330f0d4ff810e, 1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a, 0b9e4bbfb7c949151e3acd44ed4aa33614d2e110, 81af4137a30c4c2dc694dea8cacb180bd66000ef, 5424e678f9b304e148cf5dcc047cffc7a56a3bb5, 9a2d9d4e657b23dc21f24cf139e3aeff0b61341f, df4601653201de21b487c3e7fffd464790cab808 |
| Linux/Linuxgeneric | 3.14 | Not reported |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 19, 2026
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.
Quoted source text, attributed separately from HOL analysis.