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NVD / CVE Program· CNA Linux

CVE-2026-90359: bpf: Reject >8 byte return values on return-reading trampoline paths

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 9a9e902bd0556052534641f7d5f868c6dc4b84ae, c48796aa6c392cde93946e5d5a9a1f1b1cf72feb, d36ac53fc83baf843c51b7afd6d2471f36b713d8.

Low priority for now. Upgrade to Linux Linux 9a9e902bd0556052534641f7d5f868c6dc4b84ae, c48796aa6c392cde93946e5d5a9a1f1b1cf72feb, d36ac53fc83baf843c51b7afd6d2471f36b713d8 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: bpf: Reject >8 byte return values on return-reading trampoline paths btf_distill_func_proto() builds the function model used for the fentry/fexit/fmod_ret/fsession trampolines and struct_ops. It has accepted a 16-byte __int128 return value since the trampoline was introduced: __get_type_size() returns the integer's type size, and the return-type check only rejected ret < 0. But the BPF trampoline preserves only 8 bytes of the return value (RAX on x86, i.e. R0). For an attach type that reads the target's return value the second half (RDX / R3) is neither saved nor restored, so a program attached to a function returning a 16-byte value corrupts the value seen by the real caller and itself observes only half of it. struct_ops trampolines have the same limitation. This affects the attach types that read the target's return value: fexit, fmod_ret and fsession (plus the _multi variants of fexit and fsession), and struct_ops. fentry/fentry_multi run before the target returns and are unaffected. Reject a >8 byte return value for these attach types in bpf_check_attach_target() and bpf_check_attach_btf_id_multi(), and for struct_ops in bpf_struct_ops_desc_init().

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 21, 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

    • 5.5affected
    • fec56f5890d93fc2ed74166c397dc186b1c25951 and later · before de54ba33690d2dd3c4aa686c9693505644285b0baffected · git
    • fec56f5890d93fc2ed74166c397dc186b1c25951 and later · before 9a9e902bd0556052534641f7d5f868c6dc4b84aeaffected · git
    • fec56f5890d93fc2ed74166c397dc186b1c25951 and later · before d36ac53fc83baf843c51b7afd6d2471f36b713d8affected · git
    • fec56f5890d93fc2ed74166c397dc186b1c25951 and later · before c48796aa6c392cde93946e5d5a9a1f1b1cf72febaffected · git
    • before 5.5not affected · semver
    • 6.12.114 and later · up to and including 6.12.*not affected · semver
    • 6.18.57 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:12linuxfrom 0—
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-2026-90357Sep 17, 2026 · wifi: mt76: mt7915: unlink TWT flow if the MCU rejects the agreement
    35Monitor
  • ← EarlierCVE-2026-90358Sep 17, 2026 · bpf, x86: Fix trampoline stack size for 128-bit arguments
    31Monitor
  • Later →CVE-2026-90360Sep 17, 2026 · regulator: core: use system_freezable_wq for init complete work
    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 Linux9a9e902bd0556052534641f7d5f868c6dc4b84aeVendor (CNA)
Linux Linuxc48796aa6c392cde93946e5d5a9a1f1b1cf72febVendor (CNA)
Linux Linuxd36ac53fc83baf843c51b7afd6d2471f36b713d8Vendor (CNA)
Linux Linuxde54ba33690d2dd3c4aa686c9693505644285b0bVendor (CNA)
debian:linux7.2.6-1 · Debian:14Package 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 (3 more)

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

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