In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: reallocate update replies for mismatched IDs
ovs_flow_cmd_new() preallocates the optional reply skb before it takes
ovs_mutex and before it knows which existing flow will be updated.
That is normally fine because the skb is sized from the request flow
identifier. That identifier also becomes the inserted flow's identifier.
For updates, however, a request with a UFID may miss the UFID lookup and
then fall back to the flow key lookup. That lookup can legitimately find
an existing key-identified flow. UFIDs are optional and the flow key is
the primary identifier.
For echoed replies, ovs_flow_cmd_fill_info() writes the matched flow's
identifier, not the request identifier used for the preallocation. A short
request UFID can therefore leave too little room for the key identifier.
The fill can then fail with -EMSGSIZE and hit the BUG_ON(error < 0) in the
update path.
Once the update target has been resolved, reallocate the reply skb if the
matched flow needs a larger reply than the request identifier allowed. Do
this before replacing the actions so the request can still fail cleanly if
the rare extra allocation fails.
Metrics
Affected Vendors & Products
| Vendors | Products |
|---|---|
| Linux |
|
No data.
No data.
References
History
Mon, 24 Aug 2026 14:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-787 |
Mon, 24 Aug 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-131 | |
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Sat, 22 Aug 2026 18:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-787 |
Sat, 22 Aug 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reallocate update replies for mismatched IDs ovs_flow_cmd_new() preallocates the optional reply skb before it takes ovs_mutex and before it knows which existing flow will be updated. That is normally fine because the skb is sized from the request flow identifier. That identifier also becomes the inserted flow's identifier. For updates, however, a request with a UFID may miss the UFID lookup and then fall back to the flow key lookup. That lookup can legitimately find an existing key-identified flow. UFIDs are optional and the flow key is the primary identifier. For echoed replies, ovs_flow_cmd_fill_info() writes the matched flow's identifier, not the request identifier used for the preallocation. A short request UFID can therefore leave too little room for the key identifier. The fill can then fail with -EMSGSIZE and hit the BUG_ON(error < 0) in the update path. Once the update target has been resolved, reallocate the reply skb if the matched flow needs a larger reply than the request identifier allowed. Do this before replacing the actions so the request can still fail cleanly if the rare extra allocation fails. | |
| Title | net: openvswitch: reallocate update replies for mismatched IDs | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2026-08-22T15:32:36.616Z
Updated: 2026-08-22T15:32:36.616Z
Reserved: 2026-08-15T05:44:03.924Z
Link: CVE-2026-74664
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-22T16:16:40.220
Modified: 2026-08-22T16:16:40.220
Link: CVE-2026-74664
Redhat