CVE-2026-90359bpf: Reject >8 byte return values on return-reading trampoline paths
- —Not scoredno CVSS score yet
- 0.20%Exploitation in 30 daysEPSS · top 90% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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().
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 34 days later
· 34 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.20% · top 90% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected fec56f5890d93fc2ed74166c397dc186b1c25951 – < de54ba33690d2dd3c4aa686c9693505644285b0b
- affected fec56f5890d93fc2ed74166c397dc186b1c25951 – < 9a9e902bd0556052534641f7d5f868c6dc4b84ae
- affected fec56f5890d93fc2ed74166c397dc186b1c25951 – < d36ac53fc83baf843c51b7afd6d2471f36b713d8
- affected fec56f5890d93fc2ed74166c397dc186b1c25951 – < c48796aa6c392cde93946e5d5a9a1f1b1cf72feb
- affected 5.5
- unaffected < 5.5
- unaffected 6.12.114 – ≤ 6.12.*
- unaffected 6.18.57 – ≤ 6.18.*
- unaffected 7.2.6 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References4
- https://git.kernel.org/stable/c/de54ba33690d2dd3c4aa686c9693505644285b0b (opens in a new tab)
- https://git.kernel.org/stable/c/9a9e902bd0556052534641f7d5f868c6dc4b84ae (opens in a new tab)
- https://git.kernel.org/stable/c/d36ac53fc83baf843c51b7afd6d2471f36b713d8 (opens in a new tab)
- https://git.kernel.org/stable/c/c48796aa6c392cde93946e5d5a9a1f1b1cf72feb (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-82020 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-90359)Record last updated .