Microsoft security update for CVE-2026-90049
🔗 CVE IDs covered (1)
📋 Microsoft's advisory
EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-90049. This page also shows what EchelonGraph holds for CVE-2026-90049, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.
🎯 Affected products3
- azl3 kernel 6.6.150.1-1 on Azure Linux 3.0
- azl3 kernel 6.6.152.1-1 on Azure Linux 3.0
- azl4 kernel 6.18.50-1.5.azl4 on Azure Linux 4.0
✅ Updates Microsoft lists: 3 updates
3 rows: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.
| KB article | Update | Fixed build |
|---|---|---|
| — | Security Update | 6.6.157.1-1 |
| — | Security Update | — |
| — | Security Update | 0:6.18.57-1.1.azl4 |
🧭 EchelonGraph on CVE-2026-90049
- EchelonGraph score
- 9.3 CRITICAL
- CISA KEV
- Not listed
- Fix status
- A fix is available — apply it.
Description from the CVE record (CVE.org), as published by its numbering authority
In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't skb_tx_error() the source skb in skb_zerocopy() skb_zerocopy() copies frags from @from into @to. On an skb_orphan_frags() failure it calls skb_tx_error(@from), a destructive operation on the source skb the copy helper does not own. That completes @from's zerocopy uarg and clears SKBFL_ALL_ZEROCOPY, including the SKBFL_SHARED_FRAG page-ownership marker. Both callers already report the failure on their own drop path. nfnetlink_queue does it at nla_put_failure, and Open vSwitch does it in the flow-miss drop arm of ovs_dp_process_packet(), so nothing is lost by dropping it here. On Open vSwitch's OVS_ACTION_ATTR_USERSPACE path the skb is not freed on this error: do_execute_actions() ignores output_userspace()'s return value and, unless the upcall was the last action, keeps forwarding the same skb through the flow's remaining actions. The uarg is completed while that skb is still in flight, telling the producer its buffers are free, and SKBFL_SHARED_FRAG is cleared on an skb the rest of the stack still handles. That flag is what makes esp_input() call skb_cow_data() instead of decrypting in place, so a later local ESP delivery can decrypt over frags the skb does not own privately. Leave error reporting to the callers.
Published by kernel.org, the CVE Numbering Authority that assigned CVE-2026-90049, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).