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NVD / CVE Program· CNA Linux

CVE-2026-90108: net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
  • Fixed version: Linux Linux 036322025d6e440cb75fc6fecbba9a16b271a2ae, 056395acb7041b3a1f2baa08d89a1938a8b8776a, 0fb9a513766071ea9d5f3bf988e39241b8e9ee3b; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 036322025d6e440cb75fc6fecbba9a16b271a2ae, 056395acb7041b3a1f2baa08d89a1938a8b8776a, 0fb9a513766071ea9d5f3bf988e39241b8e9ee3b; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: net/smc: free stashed qentry before overwrite in REQ_ADD_LINK to ADD_LINK transition When smc_llc_event_handler() transitions the local LLC flow from SMC_LLC_FLOW_REQ_ADD_LINK to SMC_LLC_FLOW_ADD_LINK on arrival of an ADD_LINK request, it calls smc_llc_flow_qentry_set() unconditionally: if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_REQ_ADD_LINK) { lgr->llc_flow_lcl.type = SMC_LLC_FLOW_ADD_LINK; smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry); ... } A CONFIRM_LINK or ADD_LINK_CONT arriving while flow->type is SMC_LLC_FLOW_REQ_ADD_LINK is stashed into flow->qentry via the SMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT handler (which stores into flow->qentry for any non-NONE flow type). When the subsequent ADD_LINK arrives, the REQ_ADD_LINK branch overwrites flow->qentry with the new pointer without first freeing the stashed allocation, leaking one kmalloc object. The stashed entry has no consumer: smc_llc_wait() is only called from llc_add_link_work, which is not yet scheduled while the flow type remains REQ_ADD_LINK. No waiter is sleeping on llc_msg_waiter at this point. It is safe to unconditionally free any stashed qentry before the overwrite. Call smc_llc_flow_qentry_del() before smc_llc_flow_qentry_set() in the REQ_ADD_LINK branch. smc_llc_flow_qentry_del() already checks flow->qentry before freeing, so the normal path where no entry is stashed is a no-op.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 10th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.16affected
    • b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 and later · before 7dd55348c0d9399a9448847819e9f3904ae507adaffected · git
    • b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 and later · before 056395acb7041b3a1f2baa08d89a1938a8b8776aaffected · git
    • b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 and later · before b08aacfb226a840628151643b6a34eecf545d311affected · git
    • b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 and later · before 0fb9a513766071ea9d5f3bf988e39241b8e9ee3baffected · git
    • b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 and later · before e25a602c45c76a7130878db72bcf6f76df04bf85affected · git
    • b4ba4652b3f8b7c9bbb5786f8acf4724bdab2196 and later · before 036322025d6e440cb75fc6fecbba9a16b271a2aeaffected · git
    • before 5.16not affected · semver
    • 6.1.188 and later · up to and including 6.1.*not affected · semver
    • 6.6.157 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-90106Sep 17, 2026 · net: bridge: arp/nd proxy: fix reading neigh ha
    0Monitor
  • ← EarlierCVE-2026-90107Sep 17, 2026 · net/smc: free pending qentry in smc_llc_flow_stop() before memset
    0Monitor
  • Later →CVE-2026-90109Sep 17, 2026 · net: sched: fix 32-bit backlog wrap in gred, bfifo and plug enqueue
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux036322025d6e440cb75fc6fecbba9a16b271a2aeVendor (CNA)
Linux Linux056395acb7041b3a1f2baa08d89a1938a8b8776aVendor (CNA)
Linux Linux0fb9a513766071ea9d5f3bf988e39241b8e9ee3bVendor (CNA)
Linux Linux7dd55348c0d9399a9448847819e9f3904ae507adVendor (CNA)
Linux Linuxb08aacfb226a840628151643b6a34eecf545d311Vendor (CNA)
Linux Linuxe25a602c45c76a7130878db72bcf6f76df04bf85Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records