CVE-2026-74664
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.
Executive briefing
The source record describes: 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. The practical risk depends on whether an affected product/version is present, reachable and configured in an exploitable way. Review the affected-product evidence and linked vendor advisories before assigning exposure status.
Evidence confidence: Low Evidence-derived, not an exploitability verdict
Severity & attack characteristics
CVSS vector:
No CVSS vector is currently available in the source record.
Technical explanation & impact
The technical mechanism is not expanded beyond the source description unless a referenced advisory supplies additional evidence. Read the linked vendor/CERT advisories for root-cause detail.
Potential impact must be interpreted from the published CVSS impact metrics and the affected component. A CVSS impact score is not proof that a particular asset is exploitable.
Affected products and versions
NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.
Remediation & validation
- Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
- Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
- Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
- Validate the remediation with a version check and vulnerability rescan, then retain change evidence.
No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.
Vendor advisories, patches & exploit references
- https://git.kernel.org/stable/c/00f987f066e802793a37dd2167459e67cf2cf2ec REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/20751193d83be2e9735d4faee71375691c09cd13 REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/23716dd9d8d46a5908536b73dc085e62f2b5c237 REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/5d1c224dd914579524a183a514c12b95095d12ce REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/696a0b9435fce9cf4f1e9ba7f6afa6bee96c97fc REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/69f40ccf85074981340847d650a9cbf9adabfbbe REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/87d0c0040b5d4b61de51ae39132c4c46709f2f77 REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/bd8ca84d48cd9a4f6fc63df26512c55e1d339927 REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Information gaps & confidence notes
These gaps indicate missing source data. CVE Watch does not fill them with guessed product, exploit or patch details.
- NVD does not currently provide machine-readable vulnerable CPE product/version entries for this record.
- No vendor advisory or patch reference was identified in the supplied CVE references.
- No CVSS vector is currently available in the source record.
- No CWE classification is currently available.
Last enrichment: 2026-11-07T16:58:28+00:00 · Source last modified: 2026-11-06T17:19:53.153