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NVD / CVE Program· CNA Linux

CVE-2026-90195: riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args

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 555fc6f1caf00ce7005e732b688da26c0dc3c5c5, 71dbd143be598954ae103feadd12692aeb0f2f88, 801ae90f8ce099187e6224cec7d72d07a4df0324.

Low priority for now. Upgrade to Linux Linux 555fc6f1caf00ce7005e732b688da26c0dc3c5c5, 71dbd143be598954ae103feadd12692aeb0f2f88, 801ae90f8ce099187e6224cec7d72d07a4df0324 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: riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args On RV64, the ABI requires sign-extension for signed 1-byte and 2-byte kfunc args. However, the RV64 JIT currently does not perform sign-extension for such kfunc args. Before commit 7ce090afbf72 ("bpf: Infer zext_dst based on static register liveness analysis"), state pruning could potentially omit zero-extension of 32-bit subregisters, which inadvertently masked the above issue by making the args appear as if they had been properly sign-extended. After that commit, the problem is exposed, causing the kfunc_call/kfunc_call_test4 selftest to fail. Fix this by extending the existing sign-extension logic to handle signed 1-byte and 2-byte kfunc args as well.

—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

    • 6.9affected
    • 443574b033876c85a35de4c65c14f7fe092222b2 and later · before 555fc6f1caf00ce7005e732b688da26c0dc3c5c5affected · git
    • 443574b033876c85a35de4c65c14f7fe092222b2 and later · before 801ae90f8ce099187e6224cec7d72d07a4df0324affected · git
    • 443574b033876c85a35de4c65c14f7fe092222b2 and later · before 71dbd143be598954ae103feadd12692aeb0f2f88affected · git
    • 443574b033876c85a35de4c65c14f7fe092222b2 and later · before f2aaa621591093cfe8224a25ef2f04a3b1e304b0affected · git
    • before 6.9not affected · semver
    • 6.12.110 and later · up to and including 6.12.*not affected · semver
    • 6.18.52 and later · up to and including 6.18.*not affected · semver
    • 7.2.6 and later · up to and including 7.2.*not affected · semver
    • 7.3 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
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-2026-90193Sep 17, 2026 · mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler
    0Monitor
  • ← EarlierCVE-2026-90194Sep 17, 2026 · ACPI: scan: fix bus ID cleanup on device_add() failures
    0Monitor
  • Later →CVE-2026-90196Sep 17, 2026 · ASoC: SOF: validate topology volume range before allocation
    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 Linux555fc6f1caf00ce7005e732b688da26c0dc3c5c5Vendor (CNA)
Linux Linux71dbd143be598954ae103feadd12692aeb0f2f88Vendor (CNA)
Linux Linux801ae90f8ce099187e6224cec7d72d07a4df0324Vendor (CNA)
Linux Linuxf2aaa621591093cfe8224a25ef2f04a3b1e304b0Vendor (CNA)
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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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 (3 more)

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

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